The Note: Mike Huckabee's Challenge To Senators Seeking The White House

— -- NOTABLES

--ANALYSIS -- ABC's RICK KLEIN: The Democratic National Committee's announcement that the party will hold six presidential debates really means that Hillary Clinton will appear at six debates. She was the only candidate or potential candidate to quickly and fully endorse the announcement - with an uncharacteristically swift Tweet. More telling was Martin O'Malley's response, measured but warning that "exclusivity does no one any favors." The fact may be that getting Clinton's buy-in is all the DNC needs to cement a debate structure. But for Clinton rivals who want as much exposure as possible, a top-down approach will be hard to hold to. If O'Malley and Bernie Sanders go rogue and participate in non-sanctioned debates, would Clinton even want to be at sanctioned debates without them?

--TODAY ON THE TRAIL: Fresh off his announcement yesterday, Mike Huckabee returns to Iowa, the scene of his rise in 2008, ABC's CHRIS GOOD notes. He tours a valve manufacturer in Oskaloosa and visits with employees. Later he'll host a rally at Living History Farms in Urbandale. John Kasich is in New Hampshire for a business roundtable in Concord and at meet-and-greet in Nashua. Hillary Clinton will be in the Bay Area today for a pair of fundraisers.

THE BUZZ

with ABC's MICHELLE MANZIONE

CLINTON ALSO TOOK AN AGGRESSIVE STANCE AGAINST REPUBLICANS: "Now this is where I differ with everybody on the Republican side," she said. "Make no mistakes. Today not a single Republican candidate - announced or potential - is clearly and consistently supporting a path to citizenship. Not one." "When they talk about 'legal status' that is code for second-class status," she added. She added that her time as Secretary of State showed her the difference of countries that include "second-class status." http://abcn.ws/1GY5MtG

MITCH MCCONELL PRAISES OBAMA -- WAIT, WHAT? You don't see this every day: Senate Majority Leader Mitch McConnell (R-KY) complimented President Barack Obama on his commitment to free trade, despite the opposition of many Democrats. "At the risk of having some of you literally faint, I want to compliment the president for the way he's handling the trade issue," he said at a Tuesday afternoon press conference. "I thought what he did last year in speaking the truth to his base was welcome and shows that he is intent on working with us to get both the Trade Promotion Authority in place and to subsequently approve, hopefully, [the] Trans-Pacific Partnership deal," he added.

WHO'S TWEETING?

@whignewtons: Look who bought http://www.sethmeyers.org  --> https://www.youtube.com/watch?v=oE29rDcFqlY&feature=youtu.be … #Carly2016

@SusanPage: Scott Walker's trump card w/Iowa evangelicals: His dad was pastor at 1st Baptist in Plainfield. Why it might matter: http://usat.ly/1ACb1rr 

@MarkMeckler: It's quite possible our next president could have a #TeaParty background. Read why in my piece for @fxnopinion http://www.foxnews.com/opinion/2015/05/05/2016-race-why-tea-party-president-is-real-possibility/ …

@PhilipRucker: NEW from Marrakech -- Clinton panelist slams media for foundation fundraising stories: "Political assassination?" http://wapo.st/1zAK7Fg 

@maggieNYT: GOP elites/Club crowd is going to come down on Huck like a ton of bricks http://mobile.nytimes.com/2015/05/07/us/politics/huckabee-vows-to-protect-programs-for-older-americans.html?referrer= …