The Note: What Will Walker Do?

— -- NOTABLES

--HILLARY CLINTON CALLS ON CHUCK GRASSLEY TO ‘STEP UP AND DO HIS JOB’: Hillary Clinton blasted Republican lawmakers Monday for not holding a hearing for President Obama’s Supreme Court nominee, Merrick Garland. She called on Sen. Chuck Grassley, the GOP chairman of the Senate Judiciary Committee, to “step up and do his job.” “He should hold a hearing, and he should schedule it as soon as the Senate returns from recess,” Clinton said Monday at an event at the University of Wisconsin-Madison, ABC’s MATTHEW CLAIBORNE reports. Clinton also argued that the battle over a new Supreme Court justice was revealing the worst in Republicans during this current presidential election cycle. “The same obstructionism that we've seen from Republicans since the beginning of the Obama administration, the same disregard for the rule of law that's given rise to the extremist candidacies of Donald Trump and Ted Cruz -- it's corroding our democracy, and it has to stop,” Clinton said. http://abcn.ws/21PYY6O

--HAPPENING TODAY -- SCOTT WALKER TO ENDORSE: Wisconsin Governor Scott Walker will announce who he’s endorsing in the Republican presidential primary this morning at 10:05 a.m. E.T. on “Midday with Charlie Sykes” on local station Newsradio 620 WTMJ. "I am a big, big fan of Scott Walker, he’s a terrific governor, he’s a strong conservative. And he has led this state and very, very effectively. Of course I would welcome Scott Walker’s support, anyone would, Scott Walker’s support would be tremendously important,” Cruz said yesterday at his rally in Rothschild, Wisconsin. Donald Trump tweeted Monday afternoon, “After the way I beat Gov. Scott Walker (and Jeb, Rand, Marco and all others) in the Presidential Primaries, no way he would ever endorse me!”

--ANALYSIS -- ABC’s RICK KLEIN: Before there’s any teamwork, maybe there can be agreement about the rules of the game. John Kasich’s campaign’s efforts to work with Ted Cruz forces to block Donald Trump – first reported by CNN – look to be stalled over a lack of trust, not to mention the fact that Cruz needs Kasich less than he needs him to just get out of the race. But there’s a powerful point that it’s not too late for Kasich and Cruz to make in unison: that they won’t support Trump as the nominee. Yes, this would be violating the pledge, a pledge that was re-confirmed by all the candidates at the latest Fox GOP debate. Yet both Cruz and Kasich are edging toward that reversal anyway. What’s the downside in making that formal, if that’s what they both believe? It wouldn’t be a partnership, but it would create a major and unprecedented moment for two candidates who need to shake the race up, and fast.

YESTERDAY ON THE TRAIL with ABC’s VERONICA STRACQUALURSI and PAOLA CHAVEZ

TRUMP AIDE SAYS CAMPAIGN WILL CONTEST SEATING OF LOUISIANA DELEGATES TO CONVENTION. Donald Trump aide Barry Bennett says the Trump campaign will contest the seating of Louisiana delegates to the Republican convention.  “The problem is that there was a secret meeting in Louisiana of the convention delegation and apparently, all the invitations for our delegates must have gotten lost in the mail,” Bennett told MSNBC’s Ari Melber. Despite winning the statewide vote in Louisiana, Donald Trump is currently tied with Ted Cruz in pledged delegates in the state, 18-18. ABC’s RYAN STRUYK and ALANA ABRAMSON report the other ten delegates – including five who were previously estimated for Marco Rubio – are unbound. “And there's a process to deal with this. It's in the certification process,” Bennett said. “And I've been with our legal team most of the morning now and we are moving forward with the complaint to decertify these delegates.” The Louisiana GOP convention delegation recently met to elect leadership and their representation on crucial convention panels, where Cruz supporters and uncommitted delegates filled all of the committee slots.

TRUMP TALKS TO TWO #NEVERTRUMP RADIO SHOW HOSTS. Monday, Donald Trump did two radio shows and was interviewed by two hosts who both belong to the #NeverTrump movement and have publicly backed Ted Cruz.  First, Trump spoke to Wisconsin talk show host Charlie Sykes of WTMJ. “Mr. Trump before you called into my show did you know I’m a #NeverTrump guy?,” Sykes asked Trump. “That I didn’t know.”  The interview was  heated and Sykes got continually frustrated by dodged questions about character, conservatism and the mogul’s past comments on Wisconsin. He asked Trump to explain his past Democratic donations and his insults at prominent conservatives. Trump defended himself saying his actions are well within what a businessman would have done in his position and saying that though it’s been harder on his business, he has been far more “Republican-oriented” in recent years, ABC’s CORINNE CATHCART reports. LISTEN: http://bit.ly/1RnE7Gk

CRUZ LAUGHS OFF TRUMP LAWSUIT. At a rally in Altoona, Wisconsin, Ted Cruz laughed off the threat of a lawsuit from Donald Trump regarding the delegate count in Louisiana. "Well, you know, I’m always amused when Donald doesn’t know what to do and so threatens lawsuits,” Cruz said. “He’s someone who’s used lawsuits his entire career to try to bully people. I think the American people are getting tired of it.” ABC’s JESSICA HOPPER reports. “He yells and screams, and curses, and attacks people, and threatens lawsuits, and attacks their wives, and attacks their families, it’s all a bunch of noise,” Cruz said. The Texas senator also commented on Trump’s interview with #NeverTrump advocate and conservative radio host Charlie Sykes where Sykes pressed Trump on showing civility and offering an apology to Cruz’s wife. “No candidate should be doing what Donald Trump did last week, which was attacking my wife and attacking my family,” Cruz added.

KASICH BLASTS CRUZ ‘TRYING TO APPEAL TO PEOPLE’S BASE INSTINCTS AND FEARS’, TRUMP FOR TRYING TO CHARGE COUNTRIES FOR U.S. SUPPORT.  John Kasich this afternoon unleashed sharp criticism of Ted Cruz’s proposal to patrol Muslim neighborhoods, saying Cruz is “trying to appeal to people’s base instincts and fears” — although he did not name Cruz. Kasich said that Muslims, too, hate terrorism — and that the government should not isolate them. This language was particularly strong for Kasich. ABC’s BEN GITTLESON reports, the Ohio governor also implicitly hit Donald Trump — also without naming him — for saying other countries should pick up the tab for U.S. support, and Cruz again (without naming his name) for his make-the-sand-glow comment.

ANTI-TRUMP SUPERPAC RESPONDS TO TRUMP ALLEGATIONS. Liz Mair, the GOP strategist behind Make America Awesome, the anti-Trump super PAC, released a statement Monday responding to Trump’s allegations that the Cruz campaign bought the rights to the nude Melania Trump photo and then gave the photo to the super PAC. Trump made the allegations Sunday on This Week in his interview with ABC’s JON KARL. “Actually, little green men who were captured by the US government and are currently being held at Area 51 telepathically communicated to me that one could find some interesting pictures of Melania Trump online at sites called things like 'Celebrity Sex Tape’ and ‘DCGazette’ and then the Freemasons personally urged me to use the image of her handcuffed in an ad targeting Mormon women. And Xenu agreed!,” Mair says in the (colorful) statement, ABC’s SHUSHANNAH WALSHE reports.

NEVER TOO EARLY -- GROWING LIST OF POSSIBLE VP CANDIDATES ON BOTH SIDES. The general election may still be 224 days away, but there is yet another cast of characters who could add more drama to the 2016 campaign for the White House. Once the Democrats and Republicans pick their candidates, the search will begin for their respective running mates. A number of names have been floated in political circles, with varying lists rendering hosts of pros and cons. ABC’s MEGHAN KENEALLY has a list of some of the top contenders, as suggested by political analysts. http://abcn.ws/1LV2B9I

IN CASE YOU MISSED IT

SECRET SERVICE WILL NOT ALLOW GUNS AT GOP CONVENTION.  A petition to allow the open carry of firearms at the Quicken Loans Arena during the GOP convention in Cleveland in July has upwards of 44,000 signatures, with supporters arguing that the ban is an infringement upon their Second Amendment rights given that Ohio is an open carry state. But will this go anywhere? ABC’s KATHERINE FAULDERS reports, the answer is no. The U.S. Secret Service said Monday that no firearms will be allowed at the Republican convention in Cleveland this July. http://abcn.ws/1Uxtvrr

WHO’S TWEETING?

@AshLeeStrong: NYT's @hillhulse on an often overlooked story: "Tired of Being Defined by Others, G.O.P. Women Speak for Themselves" http://nyti.ms/1MOAe81 

@steveholland1: Obama says journalists partly to blame for tone of presidential race, by @robertarampton http://www.reuters.com/article/idUSKCN0WV03X …

@BillKristol: Half of Republicans and GOP leaners open to a third party candidate. http://nbcnews.to/1USrplp 

‏@WisVoter: Trump hits talk radio buzz saw, heads to Paul Ryan's home town, Walker to weigh in. GOP race takes some WI twists : http://bit.ly/1RLTieE 

@BuzzFeedBen: The Name Of Whoever Is Helping The Government Hack Into An iPhone Is A Mystery http://www.buzzfeed.com/sheerafrenkel/people-want-to-know-who-is-helping-the-govt-hack-an-iphone?utm_term=.ud82JmZmYv … via @sheeraf @buzzfeednews