The US general election campaign has effectively begun, after another trio of state primary wins for Mitt Romney prompted his aides to declare victory in the Republican contest to challenge President Barack Obama.
Vowing to defeat Mr Obama in November's general election, he pledged to replace the president's 'government-centred society'
After President Barack Obama attacked him by name for the first time, Mr Romney denounced his rival as an "out-of-touch liberal" deluded after "years of flying around on Air Force One" with "true believers".
Vowing to defeat Mr Obama in November's general election, he pledged to replace the president's "government-centred society" with an "opportunity society led by free people and free enterprises".
In a speech yesterday in Washington DC – whose primary he won alongside Maryland and Wisconsin on Tuesday – Mr Romney accused Mr Obama of running a "hide-and-seek campaign".
"While I understand why the President doesn't want to run on his record, he can't run from his record either," he said. "Unlike the President, I have a record that I am proud to run on".
The former Massachusetts governor then headed to Pennsylvania, where he hopes to deliver a final knock-out blow to rival Rick Santorum in the party primary in the former senator's home state on April 24.
Mr Romney's senior aides declared that the Republican contest was already over. Stuart Stevens, his chief strategist, said: "Santorum is not going to be the nominee. Romney is."
Mr Romney has collected 655 state delegates and is on track to pass the 1,144 finish-line before August's party's convention. Mr Santorum, trailing with a distant 278, requires a miraculous turnaround.
Polls put the front-runner ahead in Connecticut, Delaware, New York and Rhode Island, all of which vote on the same day as his potential final showdown with his Right-wing rival in Pennsylvania.
Convinced that Mr Romney is his opponent, Mr Obama this week embarked on a campaign in which he is to paint him as an out-of-touch multimillionaire who backs "social Darwinist" economic reforms.
His campaign this week spent $1.4 million (£882,445) on a TV attack advertisement in key battleground states that ties Mr Romney to the oil industry and pictures his face frozen in an unflattering grimace.
Mr Romney yesterday retaliated with an advertisement, declaring: "The Obama attack machine has started" and pointing out the price of petrol had doubled in five swing states under Mr Obama.
However the clip was available only over the internet, prompting suggestions that the bruising primary contest had badly drained Mr Romney's funds and forced him to seek free advertising.
Mr Romney yesterday addressed a convention of newspaper executives in Washington, who were told by Mr Obama on Tuesday that the Republican budget plan was a "Trojan Horse" for a radical reshaping of government that would destroy the American Dream in order to give tax cuts to billionaires.
"President Obama came here yesterday and railed against arguments no one is making – and criticised policies no one is proposing," Mr Romney said.
It's one of his favourite strategies – setting up straw men to distract from his record".
Unlike the president, Mr Romney took the opportunity to attack the media, lamenting the lack of "editors to exercise quality control" in the age of Twitter and other social media. "I miss the days of two or more sources for a story – when at least one source was actually named," he added.