There is a tradition in politics called "debating the empty chair".
Candidate A challenges Candidate B to a debate. Candidate B declines. Candidate A goes ahead with the event, and speaks on a stage with an empty chair next to him or her, symbolizing Candidate B's refusal.
Candidate A wants to be seen as taking the high ground, working to get the issues in front of the voters, while Candidate B is concerned only with political tactics.
John McCain is attempting to turn that idea on its head. McCain has proposed postponing his first debate with Barack Obama, which is scheduled for tomorrow, until after Congress acts on a financial bailout bill. Obama wants to go ahead with the debate on schedule.
The way the candidates have been talking up to now, it sounds as though Obama might be debating an empty chair tomorrow night. But, in this case, it's McCain who is trying for the moral high ground.
McCain wants to be seen to be more concerned about solving a national crisis, than engaging in partisan politics. Commentators are speculating about his motives. As with everything a politician does, I suspect both candidates motivated by some combination of self-interest and concern about the national interest.
Obama's public position is that the debate is even more important, under the current circumstances. Partisanship is often talked about in negative terms but, as I wrote here, it has positive functions to perform. In the current case, a clash of ideas between the two parties may well improve any legislative product that comes out of the congressional process.