NEWS ANALYSIS - Parties play to partisan rancor - Angry sparring has largely served political interests on each side, but the confrontational tactics create risks.

But there were few real tears in the Capitol for the current state of affairs.

Seven months into Democrats' control of the House and Senate, the angry sparring has largely served the political interests of both parties, whose leaders often believe they have more to gain by warring with their rivals than by working with them.

Newly empowered Democrats, confident that the public backs their agenda and eager to expand their House and Senate majorities next year, have little incentive to accommodate the GOP minority.

They left town touting their successful efforts to raise the federal minimum wage, revamp ethics and lobbying rules, and implement the Sept. 11 commission's recommendations, though many other major goals, such as ending the war in Iraq, were unrealized.

For their part, Republicans, who still lag in public opinion polls after losing the majority last year, see more advantage in disrupting congressional business in their quest to cast the Democratic Congress as ineffective.

They went home complaining of a "do-nothing" Congress, even after they used one procedural tactic after another to stall legislative business.

"This is an era of partisan gridlock," said Julian E. Zelizer, a congressional historian at Princeton University, who pointed to the polarizing influences of the Iraq war and the fast-approaching 2008 election season.

In one of the session's last debates, the two parties clashed bitterly over a Bush administration demand to modify the Foreign Intelligence Surveillance Act of 1978 to expand the authority of U.S. spy agencies to monitor overseas phone calls and e-mails. The measure ultimately passed over the objections of many House and Senate Democrats, and President Bush signed it into law Sunday.

Few expected a flowering of comity when control of the Capitol shifted in January after 12 years of nearly total GOP rule.

The parties were coming off a fiercely contested election. Democrats, who won narrow majorities in both chambers, were smarting from years of iron-fisted tactics by the Republican majority. They were determined to challenge the White House and enact their priorities after years in the wilderness.