WASHINGTON - Barack Obama routed Hillary Clinton in a trio of Washington DC-area nominating clashes, carving into his faltering White House rival's core power base of white, women and working class voters.
The surging Democrat coasted to crushing victories in Virginia, Maryland and the US capital on Tuesday, lifting his consecutive wins since last week's neck-and-neck Super Tuesday nationwide showdown to eight.
Presumptive Republican nominee John McCain meanwhile landed his own triple primary triumph, but a tougher-than-expected showing from rival Mike Huckabee in Virginia reflected his struggle to close the deal with conservatives.
Another grim night for Clinton left her further behind Obama in the crucial count of convention delegates, and desperate for victories in Texas and Ohio on March 4, the next big night of nominating clashes, to keep her hopes alive.
Senator Obama, 46, celebrated in midwestern Wisconsin, where he hopes to drive another dagger into Senator Clinton's bid to be the first woman president on February 19.
"We won the state of Maryland. We won the Commonwealth of Virginia. And though we won in Washington, DC, this movement won't stop until there's change in Washington, DC," he said.
Obama barely referred to Clinton, instead turning his fire on McCain, in a preview of a potential November general election matchup.
"John McCain is an American hero. We honor his service to our nation," said the Illinois senator who has rocketed to the forefront of US politics in just four years, on a quest to be America's first black president.
"His priorities don't address the real problems of the American people, because they are bound to the failed policies of the past."
As Clinton's team suffered another night of losses, her deputy campaign manager Mike Henry reportedly resigned, two days after the former first lady decided to replace her campaign manager Patti Solis Doyle.
But a defiant Clinton showed no sign of giving up the fight.
"We're going to sweep across Texas in the next three weeks, bringing our message about what we need in America, the kind of president that will be required on Day One to be commander in chief, to turn the economy around," she said after flying west even before Washington area voting had closed.
"I'm tested. I'm ready. Let's make it happen!" she told a rowdy rally in El Paso in a veiled reference to Obama's perceived inexperience.
McCain, 71, also seemed to preview a contest with Obama, striking the charismatic Democrat's signature theme of "hope."
"Hope, my friends, is a powerful thing. I can attest to that better than many, for I have seen men's hopes tested in hard and cruel ways that few will ever experience," said the former Vietnam war prisoner.
"I do not seek the presidency on the presumption that I am blessed with such personal greatness that history has anointed me to save my country in its hour of need.
"I seek the presidency with the humility of a man who cannot forget that my country saved me."
With most of the vote counted, Obama led Clinton 64 percent to 35 percent in Virginia, 75 percent to 24 percent in Washington, and 60 percent to 37 percent in Maryland.
In a rolling count of nominating delegates by RealClearPolitics.com, Obama led with 1,259 to 1,210. A total of 2,025 delegates is needed for the nomination.
McCain led Republicans with 797 delegates to Huckabee's 240. Republicans need 1191 for the nomination.
Exit polling showed Obama making inroads into Clinton's support base, in a trend that if reflected nationwide, could spell disaster for her.
In Maryland, Obama won among men and among voters of every age group and income level, expanding his political base and auguring well for key states to come.
Exit polls in Virginia showed Obama triumphing in the former first lady's normal bastion of women 58 percent to 42 percent, and splitting another of her key power bases, white voters.
He won 90 percent of black voters and extended his hold on younger voters, many of whom are being turned on to politics for the first time by his soaring rhetoric and message of hope.
On the Republican side, McCain's hardest fought battle was in Virginia. With 99 percent of Republican precincts there reporting, McCain led Huckabee by 50 to 41 percent.
Exit polls showed McCain won conservatives by 43 percent to 36 percent in Maryland, but lost out to Huckabee 51 percent to 38 percent in the more conservative Virginia.
© 2008 Agence France Presse