Mitt Romney made a big leap toward winning the Republican US presidential nomination with a clean sweep of three primaries yesterday that handed a stinging defeat to chief rival Rick Santorum.
The victories in Wisconsin, Maryland and Washington, DC will increase appeals from Republican party leaders for Mr Santorum to quit so that Mr Romney can gird for a difficult fight against president Barack Obama in the November 6th election.
In his victory speech in Milwaukee, Mr Romney ignored Mr Santorum and gave voters a sense of what the general election campaign will be like, sharply criticising Mr Obama for his handling of the US economy and high petrol prices.
"It's enough to make you think that years of flying around on Air Force One, surrounded by an adoring staff of true believers telling you what a great job you are doing, well, that might be enough to make you a little out of touch," Mr Romney said.
In a clear sign that Mr Obama sees Mr Romney as his chief obstacle to re-election, the president singled him out by name and criticised him in a speech with a sharp partisan tone yesterday.
The trio of defeats puts conservative Mr Santorum's campaign in serious trouble. He is badly trailing Mr Romney in both delegates and fundraising.
Mr Santorum, a former Senator, vowed to stay in the race at least until April 24th when his home state of Pennsylvania votes and where he is hanging on to a lead in the polls over Mr Romney.
That date looms as a potentially decisive one, with Mr Romney likely to win five states that hold contests then and planning a big challenge to Mr Santorum in Pennsylvania.
Yesterday's victories widened Mr Romney's lead over Mr Santorum in delegates to an estimated 640-264, according to CNN. Mr Romney now has more than half of the 1,144 delegates he needs to clinch the nomination at the Republican convention in August.
Mr Santorum wants to win enough delegates to deny his opponent an outright victory before the convention in Tampa.
"Who's ready to charge out of the locker room in Pennsylvania for a strong second half?" Mr Santorum said to cheers in a speech after yesterday's result. "This isn't half time. We're hitting the field. The clock starts tonight.
"We don't win by moving to the middle. We win by getting people in the middle to move to us and move this country forward," Mr Santorum said.
A Quinnipiac University poll showed Mr Santorum ahead of Romney in Pennsylvania by 41 to 35 per cent, but the former private equity executive's campaign and its allies are likely to spend big on negative ads against Mr Santorum in the coming weeks.
Mr Obama hit out at Mr Romney yesterday for backing a controversial Republican budget plan authored by a key Wisconsin backer of Mr Romney, congressman Paul Ryan.
"He said that he's very supportive of this new budget and he even called it 'marvelous,' which is a word you don't often hear when it comes to describing a budget," Mr Obama said in a speech.
Mr Romney fired back that Mr Obama was trying to deflect blame for high gasoline prices that are hitting American wallets hard and could make Mr Obama's re-election tougher to achieve.
"So the president put an ad out yesterday, talking about gasoline prices and how high they are. And guess who he blamed? Me!" Mr Romney said in Waukesha, Wisconsin.
"Maybe after I'm president I can take responsibility for things I might have done wrong. But this president doesn't want to take responsibility for his mistakes."