Barack Obama has launched a counter-attack after a week of pummelling by his White House rival John McCain, dismissing the Republican as being “in the pocket” of profit-pumping US oil giants.
The Democratic hopeful, who turned 47 on Monday, went on the offensive as daily tracking polls showed Mr McCain had battled back to tie the intensifying presidential election duel, exactly three months before voters make their choice.
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In a hard-hitting new campaign ad, Mr Obama accused Mr McCain of taking campaign contributions from big oil firms as petrol prices soar and bite deep into the budgets of American families.
“Now big oil's filling John McCain's campaign with $US2 million ($A2.15 million) in contributions,” the ad's narrator said.
The spot also linked McCain to Republican president George W Bush, seeking to saddle him with the low approval ratings of the current White House resident, who Democrats say sides with former oil industry colleagues.
“After one president in the pocket of big oil… we can't afford another,” the ad said, as Mr Obama laid out his new energy plan in Michigan, the home of the struggling US auto industry and a crucial battleground state.
Mr McCain's campaign denied the senator had taken “Big Oil” donations, accused Mr Obama of trawling for contributions from oil industry employees, and pressed home its claim that Mr Obama's fame masked political liabilities.
“Barack Obama's latest negative attack ad shows his celebrity is matched only by his hypocrisy,” McCain's spokesman Tucker Bounds said.
“After all it was Senator Obama, not John McCain, who voted for the Bush-Cheney energy bill that was a sweetheart deal for oil companies,” he said, referring to Vice-President Dick Cheney.
Republicans also pounced on Mr Obama's call on Monday to sell 70 million barrels of oil from the US Strategic Petroleum Reserve in a bid to lower prices, pointing out he had opposed such a plan a month ago.
Offshore drilling row
Mr Obama's foes also accuse him of backtracking for political gain on the question of expanding offshore drilling, which he has opposed but now says he would accept if it would ease political deadlock over sweeping energy reforms.
Republicans also mocked Mr Obama by delivering tyre gauges to reporters, highlighting the Democrat's comment that drivers could save gas by properly inflating tyres, which Mr McCain claims is proof Mr Obama's energy plan is shallow.
The Obama campaign noted, however, the US Department of Energy and the NASCAR auto racing series advise drivers to keep tyres inflated to improve petrol mileage.
During his speech in Michigan, Obama vowed to launch a $US150 billion ($A161.4 billion) effort to cut America's reliance on oil from volatile regions of the globe.
“This addiction is one of the most dangerous and urgent threats this nation has ever faced,” he said, blaming it for wiping out pay cheques, breeding instability in the Middle East and provoking global warming.
Tax plans savaged
“In 10 years, we will eliminate the need for oil from the entire Middle East and Venezuela,” he said, and called for a windfall tax on oil company profits to finance a $US1,000 ($A1,076) rebate for families hit by high energy costs.
Republicans have savaged Mr Obama's plan for a windfall tax, arguing it would do nothing to cut the price of petrol at the pump.
The row over energy coincided with a new Rasmussen daily tracking poll showing Mr McCain and Mr Obama locked in a tie – 44 per cent each.
When undecided voters who were “leaning” to one candidate or the other were included, Mr McCain led by 47 to 46 per cent, the first time he had posted an advantage since Mr Obama secured the Democratic nomination in June.
The latest Gallup daily tracking poll had Mr Obama leading Mr McCain by a single point, 45 to 44 per cent, after a week in which McCain ads portrayed his rival as an empty celebrity suffering from a Messiah complex.