Bush joins the attack as Republicans target Obama

As the surviving presidential candidates fan out across Texas and Ohio for what is shaping up as a decisive vote next Tuesday, the Republicans are treating Barack Obama increasingly like the presumptive Democratic nominee – and pummelling him for it on everything from foreign policy to free trade.

John McCain, who has the Republican nomination all but sewn up, has led the anti-Obama charge, seeking to portray him as naive on the threat from al-Qa'ida and lambasting him for his pledge to meet certain hostile foreign leaders "without preconditions" if it seemed appropriate.

Even President George Bush has echoed some of these criticisms, describing Senator Obama's idea of meeting leaders like Raul Castro of Cuba or Mahmoud Ahmadinejad of Iran as "extremely counterproductive".

Senator Obama, for his part, has also shown signs of acting more like the presumptive nominee, focusing his campaign speeches less on attacking his Democratic Party rival Hillary Clinton and more on going after both the Bush legacy and Senator McCain's apparent determination to continue it on several policy fronts.

Just as Senator Clinton is making furious efforts to hold on to her once formidable leads in Texas and Ohio and keep a meaningful toehold on a race that is slipping away from her, Mr Obama is clearly trying to create an aura of inevitability about his candidacy and begin rehearsing lines for the long election campaign.

Speaking in Ohio on Thursday, Mr Obama told supporters the country stood on the brink of an eminently avoidable recession and made no bones about who was to blame. "This was not an inevitable part of the business cycle," he said. "It was a failure of leadership in Washington – a Washington where George Bush hands out billions of tax cuts to the wealthiest few for eight long years, and John McCain promises to make those same tax cuts permanent."

When Mr McCain tried to make hay from Tuesday night's Democratic debate in Cleveland and suggested Mr Obama did not know al-Qa'ida had a presence in Iraq, Mr Obama hit straight back. "I have some news for John McCain," he said. "There was no such thing as al-Qa'ida in Iraq until George Bush and John McCain decided to invade Iraq."

The Obama campaign also reacted to a Canadian television news report, quickly seized upon by Mr McCain, that campaign staff had told Canadian diplomats not to worry about the candidate's vigorous campaign criticisms of the North American Free Trade Agreement – deeply unpopular among blue-collar workers, especially in Ohio – because they did not represent his true policy position. Mr McCain's attacks were quickly blunted, however, when both the Obama campaign and the Canadian embassy in Washington denied they had had any contact at all.

For all the excitement and anticipation surrounding the Obama campaign, the Democratic race is far from over. The Clinton campaign just announced it raised a stunning $35m (£18m) in February, almost triple its takings from the previous month and more than enough to maintain field offices and a TV advertising barrage in the remaining primary and caucus states.

The Obama campaign appears to have raised more that that – there are no official figures yet but estimates suggest a haul of $50m or more for the month – but can no longer hope that Mrs Clinton will go bust any time soon. Across the board, the news is cautiously hopeful for the Obama camp but not a foregone conclusion. A round of new polls now puts the Illinois senator ahead in Texas by anywhere from four to seven points – two weeks after he was said to be trailing in the state by a double-digit margin. Mrs Clinton's once overwhelming lead in Ohio has now been cut to six or seven percentage points, and she is barely ahead even in the Clinton-friendly state of Pennsylvania, which votes on 22 April.

The polling figures are extremely volatile, however. The all-important Latino vote in Texas, for example, has been measured as going anywhere from 66 per cent pro-Hillary to just level pegging with Mr Obama.

*John McCain faces an intriguing question about his eligibility for the presidency because he was born in the Panama Canal Zone, not the US. The constitution allows only "natural born" citizens to run for president (disqualifying Arnold Schwarzenegger, for example), but it is not clear if that phrase means born of American parents (which McCain is) or born on American soil (which he wasn't).