The Note: And Then There Were Five

— -- NOTABLES

--WHAT COMES NEXT: Fiorina will host a live online town hall this morning. Her book, "Rising to the Challenge: My Leadership Journey," will be released tomorrow. And over the next week, she plans to make stops in the critical early primary and caucus states of Iowa, New Hampshire and South Carolina. Meanwhile, Carson will hold an announcement event in his native Detroit this morning.

--ANALYSIS -- ABC's RICK KLEIN: The Republican Party's demographic challenges are too complicated and too acute to solve on or by a debate stage. But for a party struggling with attracting a diverse, young, and female electorate, the emerging field is remarkable. The six Republican candidates expected to be in by Tuesday will include two Latinos (both in their 40s), an African-American, and a woman. More white males are on deck, of course. Still, this represents a considerable range of backgrounds, if not necessarily issue viewpoints, for a GOP that's all too aware of its short- and long-term prospects. None of this guarantees electoral success. But it does help prompt the kinds of conversations Republican leaders are seeking over the next 18 months.

THE BUZZ

with ABC's VERONICA STRACQUALURSI

5 STORIES YOU'LL CARE ABOUT THIS WEEK. What sounds most promising, taking the bridge to where Chris Christie is, or taking the train to where Rand Paul isn't? Dancing with Bernie Sanders, or debating with Tom Cotton? Trying to fill Michael Grimm's shoes on Staten Island, or trying to fill the silence of an empty stadium in Baltimore? Announcements are flying, roadways are open and cities are, too. ABC's RICK KLEIN looks at the five stories the ABC News political team will be tracking in the week ahead. http://abcn.ws/1DUQ3p6

NOTED: MARTIN O'MALLEY "WOULDN'T THINK OF ANNOUNCING ANYPLACE" BUT BALTIMORE. As the political discourse surrounding Baltimore has ramped up, especially among 2016 hopefuls, former Democratic governor of Maryland and potential Hillary Clinton challenger, Martin O'Malley, said yesterday that the situation in Baltimore would be central to his campaign. "We have deep problems as a country, and we need deeper understanding if we're going to give our children a better future," O'Malley said on NBC's "Meet the Press," according to ABC's KATHERINE FAULDERS. O'Malley also defended his record as Baltimore's mayor -- a job he held before becoming Maryland's governor. When asked if he would announce in Charm City that he's running for president, the Democratic presidential prospective replied: "I wouldn't think of announcing anyplace else."

WHO'S TWEETING?

@CarlyFiorina: I'm in and I'm excited to hear from you on @periscopeco at 4 pm EST this afternoon. http://apple.co/1EXjtoJ

@ZekeJMiller: .@CarlyFiorina watching @HillaryClinton in her announcement video #meta https://carlyforpresident.com/meet-carly/a>

@McCormickJohn: @ScottWalker and Absentee Governors Get Heat for Too Much Time on Presidential Trail: http://www.bloomberg.com/politics/articles/2015-05-04/scott-walker-and-absentee-governors-get-heat-for-too-much-time-on-presidential-trail

@katie_glueck: Carson on why he doesn't talk much about race: as a neurosurgeon, sees it's the brain that makes people who they are, not hair or skin color

@BrentBozell: 5 straw poll wins in SC 4 @SenTedCruz early proof true conservative can win http://thesouthcarolinaconservative.com/2015/04/28/sc-ted-cruz-sweeps-5-official-gop-straw-polls/ @ForAmerica @limbaugh @seanhannity #tcot