When taking questions from lawmakers at today's fiscal discipline summit, President Obama looked first to his former campaign nemesis.

Obama called on Sen. John McCain (R-Ariz.) first at the closed-door meeting, Sen. Claire McCaskill reported via Twitter. McCaskill, a maven of the social networking site, has been tweeting the meetings at the White House fiscal summit throughout the afternoon.

There was no immediate indication what McCain asked Obama, his Democratic opponent in the 2008 presidential campaign.

The summit is currently wrapping up at the White House, and Obama is fielding questions from lawmakers and economists who have been huddled to suggest solutions to the country's long-term fiscal problems.