By MICHAEL FALCONE ( @michaelpfalcone ) and AMY WALTER ( @amyewalter )

NOTABLES:

• PLANET TRUMP: Donald Trump still has a certain gravitational pull in Republican circles and tonight Mitt Romney will be squarely in his orbit. On the same day that Romney is all but certain to officially clinch the GOP presidential nomination, the former Massachusetts governor will appear with the reality television star and "birther" theorist in Las Vegas. As ABC News Political Director Amy Walter points out, the appearance reflects Romney's challenge to keep parts of the GOP base engaged, while also not turning off moderates.

• DO THE MATH: Texas holds its primary today, and 155 delegates are up for grabs. To surpass the magic number of delegates he needs to secure the Republican presidential nomination - 1,144 - Romney will need just 45 percent of the vote in the Lone Star State.

• MICHELLE OBAMA'S NEW BOOK: First Lady Michelle Obama sat down with "Good Morning America" co-anchor Robin Roberts this morning to talk about her new book about gardens titled "American Grown." She also weighed in on beets ("You either love them or you hate them") and Beyonce ("I love her to death").

• VEEP BEAT: Marco Rubio travels to Guantanamo Bay, Cuba Tuesday to conduct oversight of the facility, tour the base, and meet with the commander of Joint Task Force Guantanamo Bay, ABC News has learned. Check out the rest of the veepstakes news below in "Veep Beat."

THE NOTE:

By the end of tonight, Mitt Romney will finally be able to say that he's got enough delegates to clinch the Republican nomination, but his appearance at a Las Vegas fundraiser with Donald Trump is a reminder that he's still not quite freed from the pull of the base.

Despite Trump's peddling of the discredited theory of "birtherism" in recent days, Romney doesn't appear to be worried.

When asked about Trump's remarks yesterday afternoon, Romney made no attempt to correct Trump, but simply stated: "I don't agree with all the people who support me and my guess is they don't all agree with everything I believe in. But I need to get 50.1 percent or more and I'm appreciative to have the help of a lot of good people."

And, it is this delicate balancing act - keeping parts of the GOP base engaged, while also not turning off moderates - that is going to be the real challenge for Romney going forward, ABC Political Director Amy Walter points out.

He needs to make sure that those conservatives who stayed at home in 2008 are motivated to come out and support him this November. But, he can't afford to look too "extreme" to those suburban voters in key swing counties like Jefferson County, Colorado or Loudon County, Virginia.

And as ABC's Rick Klein notes, Romney's joint appearance with the reality television and real estate mogul is also a "reminder of the campaign's future. Romney wouldn't campaign with The Donald unless he thought he needed him. In the kind of razor-thin race Romney is expecting, he'll need more than the passive backing of 'birthers' and other fringe elements of the GOP, and that means even Trump - with his revived birther nonsense - isn't worth offending."

His decision to stand side-by-side with Trump notwithstanding tonight is the culmination of a year of campaigning for Romney. As Texas holds its primary, 155 delegates are up for grabs. To surpass the magic number of delegates he needs to secure the Republican presidential nomination - 1,144 - Romney will need just 45 percent of the vote in the Lone Star State.

ROMNEY'S NOMINATION IN ONE SENTENCE: The Washington Post's Phil Rucker writes today, "[The] Republican Party will have selected an unlikely standard-bearer for 2012: a New Englander in a party rooted in the South; a man of moderate temperament in a party fueled by hot rhetoric; a Mormon in a party guided by evangelical Christians; a flip-flopper in a party that demands ideological purity." http://wapo.st/Jq48yu

OBAMA CAMPAIGN CELEBRATES TRUMP DAY. A new video sent out this morning from Obama campaign headquarters remind us that Chicago would love nothing more than to talk about the close alliance between Romney and Trump. The video shows clips of 2008 GOP nominee Sen. John McCain correcting voters who said President Obama is an "Arab" or a "Muslim" followed by clips of Trump spouting his "birther" talk. "As the Republican nominee, John McCain stood up to the voices of extremism," the video notes. "McCain and Romney, two Republican nominees. Only one willing to lead." WATCH: http://bit.ly/KN0yBS

ROMNEY CAMPAIGN FRAMES THE WEEK: A Romney campaign aide passes along this week's messaging from Boston: "Why has this been the worst economic recovery since The Great Depression? President Obama is fundamentally hostile to job creators - both in his rhetoric and in his policies. … President Obama has never managed anything other than his own personal narrative. He has never created a job and never run a business. President Obama not only doesn't understand the economy - he also opposes the free-market principles that built it. His policies have prevented businesses from growing, thriving, and creating jobs, and he has no plans to change course. He will double down on these failed policies if given a second term. … Mitt Romney knows that the free enterprise system has created more jobs and lifted more people out of poverty than any government program in history. Starting on Day One, President Romney will remove the burdens that the Obama Administration has placed on businesses and allow them to start hiring again." The Romney campaign released an accompanying web video this morning focusing on the failed energy company, Solyndra. WATCH: http://mi.tt/Ko291P

 

MICHELLE OBAMA'S NEW BOOK: First Lady Michelle Obama spoke today with "Good Morning America" co-anchor Robin Roberts about her new book, "American Grown." The first lady's book about gardens benefits the National Park Foundation. WATCH: http://abcn.ws/KNRyN8

 

TEXAS PRIMARY PRIMER. Everything's bigger in Texas, and today's state and presidential primary is no exception, reports ABC's Elizabeth Hartfield.  As we noted above, Mitt Romney is expected to reach (and surpass) 1,144 delegates tonight-the magic delegate number needed to officially win the GOP nomination. But there's also the Republican Senate primary, which is so far the most expensive Senate race in this election cycle. Some $25 million has been spent on behalf of the candidates seeking to fill the seat left open by Kay Bailey Hutchison's retirement. Although the list of candidates on the ballot is long, the race is mostly considered to be contained to David Dewhurst, the state's lieutenant governor, and Ted Cruz, the former solicitor general.  http://abcn.ws/L0j1cw

THE SENATE PRIMARY HAS BEEN A COSTLY, BITTER FIGHT. And it may not end today.  Texas election code stipulates that candidates must receive at least 50 percent of the vote to win their party's nomination outright. If no candidate reaches that mark, the top two candidates go into a runoff, which would take place  July 31. Polls show Dewhurst ahead, but shy of the 50 percent mark. A Dewhurst/Cruz runoff looks like a strong possibility.  http://abcn.ws/ JKsrxf

NOTED: ABC's Chris Good points out that the major presidential-primary story of the day could again be Obama's vote total after his weak showings recently in West Virginia, Arkansas and Kentucky. Obama could take around 60 percent again in Texas, where the ballot includes three other candidates, including Tennessee lawyer John Wolfe, who won 42 percent in Arkansas last Tuesday. Obama polls poorly in Texas, but not as poorly as in those states: when Gallup ranked Obama's 2011 approval in all 50 states in January, Texas gave him the 18th worst showing - compare that to West Virginia (5th), Arkansas (7th), and Kentucky (11th). Voters cannot vote "uncommitted" or write in, leaving Wolfe, investor Bob Ely, and political-history author Darcy G. Richardson to vie for non-Obama votes among those who ask for Democratic ballots or seek out Democratic polling places.

 

THE BUZZ

with ABC's Elizabeth Hartfield (@LizHartfield)

VIDEO OF THE DAY. ROMNEY'S SHORT LIST: RUBIO, PAWLENTY RISING, DANIELS SLIDING. In the latest episode of his ABC News/Yahoo! Power Players Series "Spinners & Winners" Jon Karl takes a closer look at some of the potential VP candidates. Karl says Sen. Marco Rubio, R-Fla., in the top tier of potential VP nominees, is showing he can play the number one role of a running mate: attack dog. And could this be a tea leaf? The latest Romney television ad features a clip of Romney walking with Tim Pawlenty - making him the first potential running mate to appear in a Romney general election ad. http://yhoo.it/JLd3Mk

LOOKING BACK ON ROMNEY'S ROAD TO 1,144. The Wall Street Journal's Patrick O'Connor reports: "The face-off between Mr. Romney and President Barack Obama has been under way for nearly two months, so the Republican delegate win is a mere formality at this stage in the White House race. But it marks an official end to a process that began with the Jan. 3 caucuses in Iowa and wrapped up in mid-April when former Pennsylvania Sen. Rick Santorum ended his presidential bid. It also serves as a reminder of how the Republican Party drew out the nominating fight by forcing many states to divide their delegates proportionally."  http://on.wsj.com/LP75w7

ROMNEY WARNS OF WORLDWIDE THREATS.  ABC's Emily Friedman reports  Mitt Romney  thanked the sacrifice of servicemen and women while warning of the grave dangers around the globe, remarking frankly that 'the world is not safe' before ticking off a list of grave security issues around the globe. "I wish I could tell you that the world is a safe place today,"said Romney, speaking before a crowd of nearly 5,000 which included servicemen and women in uniform. The sizable crowd is one of the largest Romney has ever drawn.  http://abcn.ws/L8HNXA

OBAMA RECALLS VIETNAM VETS TREATMENT.  ABC's Jon Garcia reports, in his second address on Memorial Day, President Obama paid specific tribute to those perished during the Vietnam War on the 50th anniversary of its beginning. He recalled the sacrifice of the troops who served there and the unjust blame that was heaped on them upon their return. "It was a national shame, a disgrace that should have never happened. That's why here today we resolve that it will not happen again," Obama told vets and their families gathered at the  Vietnam War  Memorial on the national mall.  http://abcn.ws/L8L2yi

FOR THE FIRST TIME IN DECADES, NEITHER PRESIDENTIAL CANDIDATE HAS SERVED. For the first time since 1944, the two primary candidates for president have no military background, notes ABC's Matt Negrin. It has been more than six decades since a presidential election didn't involve a veteran. Sen. John McCain was a prisoner of war as a Navy aviator; former President George W. Bush was in the Air National Guard and Sen. John Kerry served in Vietnam; Al Gore was in the Army; Bill Clinton never served but Bob Dole did; and every president from George H.W. Bush to Harry Truman was in a branch of the military.  http://abcn.ws/ KZaNVA

BARNEY FRANK'S AWKWARD HOODIE JOKE. Barney Frank, the retiring Democratic congressman from Massachusetts, never known to speak anything but his mind, used his address to graduating seniors at the University of Massachusetts at Dartmouth Sunday to make a cringe-inducing joke about hoodies, reports ABC's Zach Wolf. "I do want to acknowledge a man who has played a  major role in diminishing inequality in Massachusetts," said Frank, referring to the activist Hubie Jones. "He's a great man and I've worked with Hubie for many years. You know he got an honorary degree today. You know when you get an honorary degree they give you one of these," said Frank, indicating the white graduation hood around his neck. "Hubie, I think you have a hoodie you can wear and nobody will shoot at you."  http://abcn.ws/MTKy3w

NEW APPROACH, BETTER RESULTS FOR SARAH PALIN.  Politico's Maggie Haberman and Emily Shultheis report: "Everyone has wondered who the Sarah Palin of 2012 would be. The answer is…Sarah Palin. Palin has made a string of successful recent endorsements, including an against-the-grain nod to Nebraska Republican Senate hopeful Deb Fischer in a three-way primary where most other conservatives, including tea-party leader Sen. Jim DeMint, backed another candidate. Rick Santorum, the last conservative non-Romney standing at the end of the primaries, endorsed there and in today's Texas primary to no great effect." http://politi.co/JREgeC

ROLLING THUNDER PRESIDENT TALKS POLITICS.  ABC's Matt Negrin caught up with the president of Rolling Thunder Washington, Ted Shpak, who's been cruising with the group since the 1980s. His focus is on getting people in Washington to take care of veterans, and he boasts of writing six bills and getting them passed. They talked about the draft, about immigration, about 2012, etc. Spoiler alert: He doesn't like President Obama.  http://abcn.ws/LWXt5s

THE POLITICS OF A FLIP-FLOP.  The Washington Post's Marc Fischer reports: "In politics, a mind can be a terrible thing to change. Attack ads featuring spinning weather vanes and double-talking candidates have become a staple of American campaigns, but consultants who make those ads say the flip-flopper charge doesn't always stick - and no one has a formula to predict exactly when it will. But there are reasons why some politicians' changes of heart strike voters as evidence of duplicity and others are accepted as the result of reasoned reconsideration - and America's cultural divide on social issues might explain why certain flip-flopper charges hit home."  http://wapo.st/JJY45g

SENATORS TAKE ON ROMNEY'S VP: PICK ONE OF US.  The Hill's Alexander Bolton reports: "Senators think a senator would make the best vice presidential pick for Mitt Romney, several of them told The Hill. Their reasoning: senators' ability to serve as president, the selection could help Romney in swing states, it would avoid a Sarah Palin-like situation and that having a senator on the ticket could help Republicans win back control of the upper chamber."  http://bit.ly/LDBNoB

IN THE NOTE'S INBOX:

DEMOCRATS LAUNCH PRE-CONVENTION INITIATIVE. At a press conference this morning in Charlotte, the Democratic National Convention Committee is launching the, "I'm There," campaign with a video that asks people to declare their participation in this summer's convention, whether in person, or online, by sharing a photo of themselves with the convention logo and a caption that says "I'm there!" WATCH:  http://bit.ly/KZcsue

PCCC-ENDORSED LORI SALDANA ANNOUNCES FIRST TV AD IN CA-52.  Democratic candidate Lori Saldana, a California state rep running in the Golden State's 52nd district, is launching her first TV ad in her campaign against blue dog opponent Scott Peters. Saldana was endorsed by the Progressive Change Campaign Committee late last month. The total buy is expected to be in the tens of thousands of dollars during the closing week of the June 5 primary fight. WATCH:  http://bit.ly/JLk2VJ

VEEP BEAT: Our daily look at all the action on the veepstakes front, brought to you by ABC's Arlette Saenz ( @ArletteSaenz ):

RUBIO HEADS TO GITMO: Sen. Marco Rubio, R-Fla. is traveling to Guantanamo Bay, Cuba Tuesday to conduct oversight of the facility, tour the base, and meet with the commander of Joint Task Force Guantanamo Bay, ABC News has learned. "This visit will allow Sen. Rubio an opportunity to better understand the role Guantanamo Bay plays in US detention operations, and examine how the military commission process for trying the terrorists housed there is proceeding," Alex Conant, a spokesman for Rubio, e-mails.  Rubio, a member of the Senate Intelligence Committee, will tour the Expeditionary Legal Complex, the Joint Task Force Guantanamo headquarters to receive an intelligence overview, meet with the Joint Task Force Commander - Rear Admiral Jeffrey Harbeson, U.S. Navy, and tour CAMP VI, the building which houses detainees.  Rubio departed Tuesday morning and will return to Miami Tuesday evening.

JEB BUSH ON GAY MARRIAGE:  During a trip to Taiwan last week, former Florida Gov. Jeb Bush called the issue of gay marriage a "distraction" in the presidential campaign, arguing that instead the candidates should focus on the economy, ABC News' Shushannah Walshe reports.  http://abcn.ws/KoxT72

CHRIS CHRISTIE: THE MASTER OF YOUTUBE:  We've all seen the bi-partisan spoof of the veepstakes produced by New Jersey Gov. Chris Christie and Newark Mayor Cory Booker, but as Melissa Hayes of The Record reports, "The self-produced satire highlighted a larger theme: Christie has removed the media filters, standing nearly alone among politicians in his vigorous use of Internet video, an effective and comfortable home for the Republican."  http://bit.ly/JriKO3

CHRIS CHRISTIE & BEYONCE:  Over the weekend, N.J. Gov. Chris Christie attended a Beyonce concert at the Revel Resort in Atlantic City with his family. Also in attendance - First Lady Michelle Obama and her daughters, Sasha and Malia.

McDONNELL HEADS TO WISCONSIN:  Virginia Gov. Bob McDonnell heads to Wisconsin late Tuesday to attend a private event in Racine, Wis. For Wisconsin Gov. Scott Walker who faces a recall vote next Tuesday.

 

WHO'S TWEETING?

  @sissenberg : On the trail with America's most hard-traveling candidate, in this week's  @NYMag.  http://bit.ly/KWx3et

@GeraldFSeib : Why the VP buzz around Portman is so loud: He's the un-Palin of 2012. My latest.  #election2012.  http://on.wsj.com/LwUTk4 via  @WSJ

@jonward11 : Newt spox  @rchammond confirms  @newtgingrich will b @ Vegas fundraiser 4 Romney tonight, & says Newt will intro Mitt @ June 11 $ event in Atl

@kenvogel : Finally, proof Bilderberg mtg. is gonna pick 2012 winner: Newly released agenda includes session: "US election challenges & opportunities.

@ZekeJMiller : ICYMI: Joe Scarborough: Mitt Romney "Cynical," "Doesn't Have A Worldview"  http://www.buzzfeed.com/zekejmiller/joe-scarborough-mitt-romney-cynical-doesnt-h

 

POLITICAL RADAR

-Mitt Romney campaigns in Colorado and Nevada. Tonight he holds a fundraiser in Las Vegas featuring Donald Trump and Newt Gingrich.

 Check out The Note's Futures Calendar:  http://abcn.ws/ZI9gV