Barack Obama had his best night of the campaign so far last night, trouncing Hillary Clinton in Maryland, Virginia, and DC. While Maryland and DC have long been known to favour Obama, Virginia was a state that Hillary Clinton had campaigned heavily in and, until the last minute, had hoped might swing her way. Obama won by almost 2-1: substantially more than Hillary Clinton won her home state of New York by on Super Tuesday.

Crucially, in the last post we wrote that Obama's success would depend on the extent to which he could peel support from those groups which Clinton had previously dominated. He did so in spectacular fashion last night. In Virginia, he won by 58 to 42 among women, 59 to 40 among those who make less than $50,000 per year, and 55 to 45 among Latinos. He narrowly lost the white vote to Clinton, 48 percent to 51 percent, but won the majority of white men in the state, 55 percent to 43 percent.

Hillary Clinton is now firmly on the defensive, and has been forced into a strategy disconcertingly similar to that adopted by Rudy Giuliani - sitting out the February states and waiting for Ohio and Texas on March 4th. The danger is obvious. Obama - with superior fundraising, a better ground operation, with a string of victories behind him and almost certain victories in Wisconsin and Hawaii coming up - will be able to gain the better media coverage and now has a good chance to pull out a close-fought victory in one or both of them. The departure of Clinton's Deputy Campaign Manager further adds to the sense that her campaign is in trouble.

We also, for the first time, saw that John McCain is now clearly preparing to face off against the Illinois senator in the November election. A new line appeared in his victory speech, clearly directed at Obama:

To encourage a country with only rhetoric rather than sound and proven ideas that trust in the strength and courage of free people is not a promise of hope. It is a platitude.

Nonetheless, McCain should feel worried. In Virginia, the Republican candidates combined to receive about 460,000 votes. Barack Obama alone took almost 620,000.  This is a staggering energy gap in a state which has not voted for a Democratic Presidential candidate since Lyndon Johnson's landslide over Barry Goldwater in 1964. With the high turnout likely to be generated by an almost certain win for the Democrats in the open Senate seat in 2008, Virginia is looking increasingly likely to be a swing state come November.