By MICHAEL FALCONE

NOTABLES

• WE KNOW THEY'RE RUNNING - SO WHY DON'T THEY JUST SAY SO? The looming 2016 presidential campaign has no shortage of putative contestants, from the big-name players like Jeb Bush and Hillary Clinton to the relative unknowns like neurosurgeon Ben Carson and former Maryland Gov. Bob Ehrlich. Most of them are talking and acting like candidates, making frequent trips to early primary states, raising money for their political organizations, lining up campaign staff, and courting support from local Republicans and key activist groups. But so far, only one has announced he's running for president: Sen. Ted Cruz, R-Texas. So what's causing the other current contestants to wait? ABC's CHRIS GOOD breaks it down: http://abcn.ws/1N97EQh

• BIG-TIMERS DON'T NEED TO DECLARE: For the likes of Hillary Clinton and Jeb Bush, perceived frontrunners whose last names precede them, there's less advantage to jumping in early. Primary voters already know who they are, so the media buzz of a campaign announcement isn't as valuable as it is for someone like Cruz.

• IT'S ABOUT THE MONEY: Candidates want to post the biggest fundraising totals they can, especially early in a campaign, in order to appear strong, impress donors and prove they're viable. For that reason, it makes sense to wait until the beginning of a quarter to start raising money. Once you're a candidate, you're bound to federal campaign-money restrictions, and you can't solicit donations over the $5,200 limit if that money will be used to support your candidacy. But until then, you can get away with a little bit more. Jeb Bush, for instance, reportedly raised money for the super PAC that will eventually back his candidacy, appearing at a $25,000-per-couple fundraiser this week. Once he becomes a presidential candidate, he must officially cut ties with the super PAC - and only ask for donations of $5,200 or less, according to the federal limit.

• AVOIDING THE MICROSCOPE - FOR NOW: Once a candidate announces, the media turns on the bright lights, turning heightened attention to a candidate's policies and record. That's one deterrent from getting in. "Better-known candidates tend to wait as long as possible to avoid full-on media scrutiny and regulatory oversight," said Eric Fehrnstrom, a senior adviser to Romney on his presidential runs.

• SOME PRESIDENTIAL RACES START EARLIER THAN OTHERS: In 2008, when the White House was similarly about to be vacated by a second-term president, Hillary Clinton announced her campaign in January 2007, while then-senator Barack Obama and Mitt Romney announced theirs in February. In 2012, things happened a bit later, with Newt Gingrich entering in May and Romney in June. Things used to get underway much, much later. Sen. Eugene McCarthy didn't announce his 1968 presidential campaign until November 1967. http://abcn.ws/1N97EQh

THE BUZZ

with ABC's VERONICA STRACQUALURSI

WHITE HOUSE CONTINUES TO BACK YEMEN AS MODEL FOR SUCCESSFUL COUNTERTERRORISM. The White House continues to hail Yemen - a country that is descending into chaos - as a model for fighting extremism, Press Secretary Josh Earnest said Wednesday. "The White House does continue to believe that a successful counter-terrorism strategy is one that will build up the capacity of the central government to have local fighters on the ground to take the fight to extremists in their own country," Earnest told reporters at the White House, ABC's MARY BRUCE notes. "That is a template that has succeeded in mitigating the threat that we face from extremists in places like Yemen." But Wednesday, the U.S. strategy in Yemen has virtually collapsed amid the fall of the American-backed government. The U.S. embassy in Yemen has been shut down and U.S. military personnel have been evacuated. See the full exchange with ABC's JONATHAN KARL: http://abcn.ws/1CPrywL

'HELL YEAH!' : JOE BIDEN HAD THE BEST TIME ON CAPITOL HILL YESTERDAY. When Vice President Joe Biden returns to his old stomping grounds in the Senate, you can always count on a moment of Biden being Biden. Biden, who was on the Hill Wednesday for an address by Afghanistan's President Ashraf Ghani, bro-ed out with Sen. Lindsey Graham, R-South Carolina, an old friend and potential 2016 rival, ABC's ARLETTE SAENZ notes. "President Graham. Do y'all know President Graham?" Biden hollered over at the reporters speaking to Graham. "He just guaranteed me I'll be Secretary of State," Biden joked. "You can be U.N. ambassador," Graham said. "You've got the skills, you really do." When asked by ABC News whether he will run for president against Graham, Biden said, "Hell yeah!" "He'll kick my butt," Graham said. "We're going to travel together, debate all over the country," Biden said before walking off. "We'll wear out every reporter," Graham said with a laugh. http://abcn.ws/1LZm1t6

AFGHAN PRESIDENT ADDRESSES JOINT MEETING OF CONGRESS. Addressing a Joint Meeting of Congress yesterday, Afghan president Mohammed Ashraf Ghani thanked America for its "generous support" of Afghanistan through nearly 14 years of conflict. "The people of Afghanistan recognize the bravery of your soldiers and the tremendous sacrifices that Americans have made to keep Afghanistan free," he said, drawing a standing ovation from the chamber. "We owe a profound debt to the 2315 servicemen and women killed and the more than 20,000 who have been wounded in service to your country and ours." Ghani called on the world's democracies to unite against Islamic extremism. "Leaders, intellectuals, and those many millions of Muslims who believe that Islam is a religion of tolerance and virtue must find their voice," he said. "Silence is not acceptable." Ghani was received warmly by lawmakers, Vice President Biden, Ambassador Samantha Power and Homeland Security Secretary Jeh Johnson, according to ABC's JOHN PARKINSON.

'CRAP' PROBLEM ON THE NATIONAL MALL: PARK SERVICE TURNS TO BORDER COLLIES TO HERD GEESE. Spring in Washington, D.C. means cherry blossoms and hordes of tourists flocking to the National Mall. And with peak season right around the corner, the National Park Service is dealing with a "crappy" problem as well. Large swaths of the National Mall are covered in feces, courtesy of the very large population of Canada Goose that make their home on the picturesque grounds. The National Park Service says that biologists estimate just one goose produces as much as "2-3 pounds" of waste per day. The geese waste may be causing major damage to the infrastructure on the National Mall, including the famous Reflecting Pool that runs between the Lincoln Memorial and Washington Monument. Cue the Collies - the Park Service wants to use border collies to fix the goose problem. ABC's KAREN TRAVERS has the dirty details: http://abcn.ws/1BqZrhQ IN CASE YOU MISSED IT

A CAPITOL HILL #PARKINGFAIL, STARRING CONGRESSWOMAN ELEANOR HOLMES NORTON. Del. Eleanor Holmes Norton may need to work on her parking skills. In video obtained by ABC News, Norton, 77, is seen exiting her vehicle Wednesday morning, which was parked awkwardly in an angled parking spot on Capitol Hill. Norton, a 12-term Democrat representing Washington, D.C., in Congress, pulled straight in to the spot, coming very close to each vehicle, according to ABC's JOHN PARKINSON and GEORGE SANCHEZ. WATCH: http://abcn.ws/19RokOb

IN THE NOTE'S INBOX

FORMER HOUSE INTEL CHAIR MIKE ROGERS ANNOUNCES NATIONAL SECURITY-FOCUSED PRESIDENTIAL FORUM IN NEW HAMPSHIRE. From a friend of The Note: "On the heels of the first presidential candidate announcement, Mike Rogers, former Chairman of the House Intelligence Committee, is announcing the New Hampshire leadership of Americans for Peace, Prosperity and Security. Additionally, Rogers announced APPS will host the first New Hampshire Presidential Candidate Forum the week of June 22. APPS will play a significant role in shaping the 2016 debate by hosting national security forums in the early presidential nominating states of Iowa, New Hampshire and South Carolina." Members of the advisory board includes: former Congressman Charlie Bass; businessman and former candidate, Dan Innis; Dean Kamen, President of DEKA Research and Development; and long-time New Hampshire political operative, Tom Rath, the former New Hampshire Attorney General.

WHO'S TWEETING?

@corymfritz: . @SpeakerBoehner: Today's Medicare vote is an important step toward reining in costs while protecting patients. http://bit.ly/1xi7ORm

@mikiebarb: Chirlane McCray has spoke to Hillary Clinton, met with Guiliani's ex-wife for advice on being First Lady: http://mobile.nytimes.com/2015/03/27/nyregion/chirlane-mccray-new-york-citys-first-lady-finds-her-voice.html

@mviser: In anticipation of the @emkinstitute opening, @JoeBiden writes about his memories of Ted Kennedy in @BostonGlobe. http://www.bostonglobe.com/magazine/2015/03/25/joe-biden-recalls-ted-kennedy-mentor-who-made-difference/iPAfl1suRW8ZPtx53fWerK/story.html …

@DavidMDrucker: . @JebBush's PAC has also packed restaurants to overflow capacity for small dollar fundraisers 4 young professionals: http://washex.am/1BNWzvk

@stevenportnoy: About three-in-ten now say they have a more negative view of Clinton in the wake of the email controversy, per new @CBSNews poll.