The grand bargain to reduce the federal debt largely depends on whether President Barack Obama or House Speaker John Boehner blinks first.
Both have a history of compromise, and they've been bonding lately on the golf course and in private White House talks.
But their conciliatory natures are about to face a severe test. Can Boehner, despite a strong conservative voting record, satisfy more hard-core conservatives who are demanding that no taxes be increased? Can Obama cool the ire of liberals who want Social Security and Medicare protected?
"The key to their success will lie in their relationship with their followers," said Steven Schier, a congressional expert at Carleton College in Northfield, Minn.
As the leader of his party, Obama has enormous influence over the political fate of congressional Democrats. So far, they've given him ample, though not always overwhelming, support on key issues. There have been misgivings over his willingness last year to extend tax breaks for the wealthy and his April agreement with Republicans to cut billions from spending.
Boehner has strong clout over the 240-member House of Representatives Republican caucus. Next to the president, no single individual has as much power in Washington. House rules make it difficult for individual members to influence policy; to do so, a member needs key committee assignments or a leadership post, and the speaker controls those.
But both men have to watch their flanks. Liberals have signaled that they're impatient with Obama; 108 of the House's 192 Democrats opposed the April spending cuts. In December, after the president agreed to extend tax cuts for the wealthy, rates due to expire at the end of that month, liberals were livid.
Now rank-and-file Democrats are concerned again. When reports surfaced earlier this week that the White House might consider changes in Social Security, House Minority Leader Nancy Pelosi, D-Calif., issued a stern warning.
"We do not support cuts in benefits to Social Security and Medicare," she said flatly.
Boehner faces challenges from the opposite corner. Die-hard conservatives have been ascendant in the House Republican caucus for years, and they don't consider Boehner a true enough believer. He lost a leadership position in 1998, and he began his most recent leadership climb in 2006 not as the conservative favorite but as the plain-spoken, collegial alternative to a House Republican leadership team that had been embarrassed by lobbying scandals. A "fresh face," Rep. Jeff Flake, R-Ariz., said at the time.
Boehner came with a reputation as a deal-maker, working in 2001-02 with Sen. Edward Kennedy, D-Mass., and Rep. George Miller, D-Calif., to craft historic legislation to overhaul the nation's education system. Conservatives were appalled, but many colleagues viewed Boehner affectionately, appreciating his ability to get things done.
Boehner, said Rep. Peter King, R-N.Y., is a conservative and realist who will "get the best possible deal you can in a negotiation."
But he has to cope with a persistent thunder from the right, where House Majority Leader Eric Cantor, R-Va., is seen as commanding significant loyalty from more ideological conservatives. Many of the House's 87 Republican freshmen were elected with the backing of the conservative tea party, and they're wary of any deal that gives anything on taxes.
