Whether looking at bills they have led on or bills they have signed onto, Mr. McCain has reached across the aisle far more frequently and with more members than Mr. Obama since the latter came to the Senate in 2005.
In fact, by several measures, Mr. McCain has been more likely to team up with Democrats than with members of his own party. Democrats made up 55 percent of his political partners over the last two Congresses, including on the tough issues of campaign finance and global warming. For Mr. Obama, Republicans were only 13 percent of his co-sponsors during his time in the Senate, and he had his biggest bipartisan successes on noncontroversial measures, such as issuing a postage stamp in honor of civil rights icon Rosa Parks.
With calls for change in Washington dominating the campaign, both Mr. Obama, the Democrats’ presidential nominee, and Mr. McCain, his Republican opponent, have claimed the mantle of bipartisanship.
But since 2005, Mr. McCain has led as chief sponsor of 82 bills, on which he had 120 Democratic co-sponsors out of 220 total, for an average of 55 percent. He worked with Democrats on 50 of his bills, and of those, 37 times Democrats outnumber Republicans as co-sponsors.
Mr. Obama, meanwhile, sponsored 120 bills, of which Republicans co-sponsored just 26, and on only five bills did Republicans outnumber Democrats. Mr. Obama gained 522 total Democratic co-sponsors but only 75 Republicans, for an average of 13 percent of his co-sponsors.
An Obama campaign spokesman declined to comment on The Times analysis.
McCain campaign surrogate Sen. Lindsey Graham, though, said the numbers expose a difference between the two candidates.
“The number - 55 and 13 - probably shows that one has been more desirous to find common ground than the other. The legislative record of Senator Obama is very thin,” said Mr. Graham, South Carolina Republican, who has teamed up with Mr. McCain probably more than any other senator.
The Times study looked at the bills each man introduced as the chief sponsor, and at the bills sponsored by other senators that each man signed onto. The study excluded resolutions and amendments, focusing instead on measures that each man authored and put into the normal legislative process.