Barack Obama defeated Hillary Clinton in Maine caucuses Sunday, winning by a sizable margin as the state’s Democrats overlooked inclement weather and turned out in heavy numbers for municipal gatherings.

Democrats in 420 Maine towns and cities decided how 24 delegates would be allotted at the party’s national convention in August.

With 99 percent of the precincts in, the Illinois Senator led in state delegates elected, 2,079-1,396, giving Obama 15 delegates to Clinton’s nine.

The Maine caucuses came after Obama and Clinton made visits there, and after Obama swept Saturday races in Louisiana, Nebraska and Washington.

Barack Obama exulted in recent victories in Maine and elsewhere, telling a crowd of 18,000 Sunday evening in Virginia Beach, Va., that his campaign has “won on the Atlantic Coast, we have won on the Gulf Coast, we have won on the Pacific Coast, and places in between.”

Going 0-4 over the weekend was enough to spark internal turmoil in the Hillary camp, with campaign manager Patti Solis Doyle being replaced by another longtime Clinton adviser, Maggie Williams.

Solis Doyle, who has run Clinton’s campaign since she entered the race in January 2007, will remain with the N.Y. Senator as a senior adviser.

She said she was stepping aside as Williams takes over and cited the strain of the extended fight for the Democratic nomination.

CNN cites a source close to the Clinton camp claiming that Solis Doyle’s job had been at risk since Clinton’s poor finish in Iowa.

Hillary’s third-place performance in Iowa coincided with the realization that the campaign had been running out of money.

This is, of course, the oldest trick in the political book. When you’re losing, you have to do something, and sacking the campaign manager gives the impression of someone taking the fall besides the candidate herself.

It did work for John Kerry, but those were different circumstances.

Whatever the reason for the shakeup, Barack Obama’s routs - particularly in Washington and Maine, where conventional wisdom suggested Clinton would be stronger - may signal his first burst of sustainable momentum.

Tomorrow is Super Tuesday II, the Potomac / Beltway edition. Virginia, D.C. and Maryland will hold primaries that have become increasingly critical for both campaigns heading into races with even more delegates at stake.