Obama sweeps Clinton in Maryland, Va., D.C.

While still in Virginia on Tuesday, Clinton did satellite interviews with 10 TV stations in Ohio, Texas and Wisconsin, calling for more debates and addressing regional concerns such as the economy in Ohio and immigration in Texas.

Asked about the possibility of sharing the November ticket with Obama — before Tuesday's results were known — she said it was too soon to talk about such things, but in an interview with WTMJ in Milwaukee she echoed the comment her rival has been making about her: "I have the highest regard for him. He was my friend before this started, and he will be my friend going into the future."

In Virginia, the parties held binding primaries on the same day for the first time.

“We have had heavy voter turnout ... throughout the state,” Susan Pollard, a spokeswoman for the Virginia Board of Elections, told NBC affiliate WRC of Washington.

In the Washington suburb of Alexandria, the previous primary record was broken by noon, WRC reported. Most were voting in the Democratic primary.

More than a third of voters in the Virginia Democratic primary said they had not voted in a primary before, as did almost one in five voters in the Maryland Democratic primary, according to the exit interviews.

In Maryland, icy weather caused traffic problems and a judge agreed to order that voting places stay open an extra 90 minutes. Ballots cast during the extended 90 minutes will be provisional ballots, as required by federal law. That means people will vote on paper, the ballots will be put in an envelope and reviewed after the election. An election official says the provisional ballots won't be counted until Tuesday, because Monday is a holiday.

But they shouldn't affect the outcome, considering the size of Obama's lead.

Kweisi Mfume, a onetime Democratic representative from Maryland and former president of the NAACP, noted exit polls in Virginia that suggested strong support for Obama among white and Latino voters. “We really have, to some extent, come of age,” he said in an interview on MSNBC.

“I think Barack Obama has a momentum that is going on not just in Maryland, not just in Virginia, but nationwide,” said Mfume, who has not endorsed a candidate.

Tom Schaller, a political science professor at the University of Maryland-Baltimore County, told NBC affiliate WRC of Washington that Obama’s message of change was effective with people who perceived Clinton as an extension of her husband’s administration.

“She’s running against the Bush era, and he’s running against the Bush and Clinton era,” Schaller said.

Picking the president: The candidates Click to visit that candidate's MSNBC page or click the XML symbol for an RSS feed. John McCain                Barack Obama

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