CLINTON REPLACES TOP AIDE AMID LOSSES (Anne E. Kornblut and Dan Balz, Washington Post) Sen. Hillary Rodham Clinton shook up her presidential campaign yesterday, replacing campaign manager and longtime aide Patti Solis Doyle with Maggie Williams, her former White House chief of staff, in an acknowledgment of the unexpectedly difficult struggle in which she finds herself against Sen. Barack Obama… The removal of Doyle, 42, was portrayed as an amicable one initiated by the campaign manager herself. But it gave credence to what some supporters have said for many weeks – that the campaign had spent too much money yielding too few results and that fresh management and advice are needed for what could be a long battle against Obama. Doyle did not tell Clinton how rapidly the campaign was burning through money, according to one campaign official, who said Clinton learned about her financial constraints only after the New Hampshire primary on Jan. 8.

MORE: Meet Maggie Williams, Hillary Clinton’s New Campaign Manager (Thomas DeFrank, New York Daily News)

HOW WILL IT ALL END? (Walter Shapiro, Salon) In truth, here is what we know about the Democratic endgame – and it is not much. After Tuesday’s vote, the next major milepost will be the March 4 mega-primaries in Texas and Ohio. But based on current trends, neither candidate will win the nomination solely from the delegates they acquire in the primaries and caucuses alone… What that means is that the 796 unelected superdelegates (mostly members of the Democratic National Committee, governors, senators and House members) will be the ones who put either Obama or Clinton over the top. According to CNN, only 359 superdelegates have so far endorsed a candidate, favoring Clinton 224 to 135 (these commitments are not binding). That calculation leaves 457 of these party insiders on the fence – and they are being wooed with an ardor that makes every day seem like Valentine’s Day. Even though the Democratic Party itself created these superdelegates after the 1980 campaign, they have always had a whiff about them of old-time machine politics and the kind of rigged conventions that nominated Hubert Humphrey in 1968 over the protests of the antiwar movement.

OBAMA’S PATH TO VICTORY (William Kristol, New York Times) If Obama wins Ohio and Texas — or even wins one — he’ll be in good shape. He should take Wyoming on March 8 and Mississippi on March 11. Then there’s over a month until the next contest, in Pennsylvania on April 22. That stretch of time could be key. It could be the moment for many of the uncommitted superdelegates to begin ratifying the choice of Democratic primary voters, and to start moving en masse to Obama. Many of these superdelegates are elected officials. They tend to care about winning in November. The polls suggest Obama matches up better with John McCain. And the polls are merely echoing the judgment of almost every Democratic elected official from a competitive district or a swing state with whom I’ve spoken. They would virtually all prefer Obama at the top of the ticket.

AS VOTING PATTERN EMERGES, SO DOES NEED TO BREAK IT (John Harwood, New York Times) That pattern — driven by demographics and electoral mechanics — has proven more powerful than momentum or the candidates’ policy messages. In the quest for delegates over the next three months, they will be wrestling the pattern as much as each other… Mrs. Clinton, of New York, who would be the first woman to be president, has dominated among women; according to exit polls, they have consistently constituted 55 percent or more of the Democratic electorate. Mr. Obama, of Illinois, who would be the first black president, has dominated among blacks by even more lopsided margins. But with the exception of a few states like South Carolina and Georgia, where blacks represented a majority and Mr. Obama won, they have represented a far smaller share of the vote. Mrs. Clinton, drawing on memories of prosperity during her husband’s presidency, has held steady advantages among Hispanics, older voters and blue-collar whites. Mr. Obama’s inspirational “Yes We Can” message has produced an edge among young people, independents, college graduates and higher-income Democrats.

MORE: Obama’s Fate Is in the Hands of the White Working Class (Michael Tomasky, The Guardian)

CLINTON BADLY NEEDS VIRGINIA VICTORY (Kenneth P. Vogel, Jonathan Martin and Lisa Lerer, Politico) Clinton – whose campaign is reeling after a high-level staff shakeup and weekend loses to Obama in Maine, Washington State, Nebraska and Louisiana – has all-but-conceded defeat in Maryland and the District. She has campaigned hard in Virginia, where her campaign has a strategy to keep things competitive, but it’s already looking ahead to March 4 contests in Ohio and Texas as a firewall of sorts. Obama leads Clinton in Virginia by 53 percent to 37 percent, according to a poll released Sunday by Mason-Dixon… Given Obama’s strength in the population centers of D.C. and its Maryland and Virginia suburbs, as well as Baltimore and downstate Virginia cities like Richmond, Newport News, Hampton and Norfolk, he’s likely to pick up the lion’s share of the congressional districts. Clinton hopes to keep Obama from rolling up a big-margin victory in Virginia by courting white suburban women, Latinos, federal workers in Northern Virginia and poor, rural whites to the south and to the west.

LOSSES SIGNAL CHALLENGES FOR MCCAIN (Paul Vitello and Michael Cooper, New York Times) Mr. McCain, who won enough delegates in the coast-to-coast nominating contests on Tuesday to place him mathematically beyond the reach of his Republican rivals, suffered embarrassing losses in the Louisiana primary and the Kansas caucuses on Saturday to former Gov. Mike Huckabee of Arkansas… Results of the weekend contests do not affect Mr. McCain’s solid lead, or change the likelihood of his winning the nomination. But they underlined the thinness of support for him among religious and social conservatives, who make up the bulk of Mr. Huckabee’s voters, and the problem that has dogged Mr. McCain’s presidential aspirations since 2000: how to overcome the distrust he elicits from that core constituency in his party while maintaining credibility as the unorthodox Republican whom moderates, independents and many Democrats like so much.

HUCKABEE SEEKS HIS MIRACLE (Michael Scherer, Time) As the polls now stand, Huckabee is a dramatic underdog heading into the February 12 primaries in Virginia and Maryland, with McCain outpolling him by a margin of two to one. But the Huckabee campaign says it has its eye fixed firmly on the March 4 primary in Texas, where Huckabee could benefit from his southern appeal, and lingering conservative skepticism on McCain’s positions on campaign finance reform and immigration. Whatever happens, Huckabee’s strategists maintain without fail that the candidate will not be swayed by pressure from fellow Republicans to bow out before one candidate reaches 1,191 delegates. On Friday, Huckabee received a call from Texas Gov. Rick Perry, asking him to leave the race, according to someone familiar with the call. Huckabee told his fellow governor no. “We don’t care. We’re not about the party. We never have been,” said Ed Rollins, Huckabee’s national chairman, backstage at the Maryland rally. “To a certain extent this is about the people. They get their choice.”

GETTING TO 270 (John Fund, Wall Street Journal) The assumption has been that Democrats have an advantage because they can supposedly win every state John Kerry took in 2004 plus Ohio, which has fallen on hard economic times and seen its state Republican Party discredited. That would give the Democratic nominee at least 272 electoral votes. But Mr. McCain’s rise to the GOP nomination throws that calculation out the window. He is the only potential GOP candidate who is clearly positioned to keep the basic red-blue template of how each state voted in 2004 intact and then be able to move into blue territory.