The Republican presidential candidate is at a big financial disadvantage compared to the likely Democratic nominee.

John Kerry raised over $40 million in March 2004 after clinching the Democratic nomination. He was still far behind George W. Bush in the money race, because the president had not had to compete in the primaries and could devote a lot of time to big-ticket fundraisers.

John McCain clinched the Republican nomination on February 5 and formally won enough delegates to be the nominee on March 4. But he only managed to raise $15 million in March. According to Marc Ambinder, Mitt Romney has promised to help McCain raise another $15 million or so from Romney supporters.

To put that in perspective, Barack Obama raised more than $40 million in March, and Hillary Clinton, who is quite the longshot for the Democratic nomination, managed to raise about $20 million that month.

At MyDD, Jonathan Singer noted that Obama raised more money in March alone than McCain raised in the entire first quarter.

I know a lot of you are worried about the continuing Democratic contest, but I think we should relax and let the rest of the primaries play out. The likelihood is that after Puerto Rico votes on June 7, Obama will be far enough ahead that the superdelegates will move decisively in his direction.

Meanwhile, McCain isn’t going to be building any kind of warchest that Obama can’t match.