Both presidential rivals are working behind the scenes to calm the increasingly incendiary atmosphere on the campaign trail, which erupted with lurid claims about Mr Obama's links with the former terrorist Bill Ayres and a lynch mob atmosphere at McCain rallies.
And a Democratic strategist who talks regularly with Mr Obama's senior advisors added: "Obama has said all along that he will work with the best people, regardless of party affiliation. John McCain has experience and he used to have a record of bipartisanship. We're all going to need to pull together when this is over."
Mr McCain will not be offered a cabinet job, but Mr Obama may ask him to spearhead a bipartisan overhaul of veteran's affairs, an issue close to Mr McCain's heart.
The claims that Mr Obama is already planning his administration come as a friend of Mr McCain revealed that the Republican candidate is concerned that the ugly rhetoric of the last week will damage his reputation as an honest patriot if he loses on November 4.
The Republican strategist, who used to work for Mr McCain, said: "John knows that his reputation as a decent man is on the line but he's got devils on each shoulder telling him to hit harder."