Filibuster Deal Heralds Stirrings of Compromise WASHINGTON - The Senate agreement to pull back from unilateral rules changes that would have eroded the power of the filibuster was hailed by both parties as the beginning of a new spirit of bipartisan cooperation that saved the Senate. But to some policy makers practiced in the art of compromise, it represented a potential missed opportunity. A Senate where 51 votes rule - not the filibuster-proof 60 - may well have empowered the political center to force compromise, taking power from the political poles, and especially from the party leadership, and returning it to potential deal makers. "With 51 votes, the majority party might just herd their people together to get whatever they want," said Senator Joseph I. Lieberman of Connecticut, the onetime Democrat turned independent. But there is another dynamic. It empowers small groups of people to affect the outcome. Mr. Lieberman, a veteran of the centrist groups that occasionally spring up to bridge the partisan gap, cautioned that it was difficult to predict what limiting the filibuster would do to the political landscape of the Senate. There do appear to be new stirrings of cooperation - or at least the desire to cooperate. On Thursday, the staunchly bipartisan group No Labels and 81 House and Senate lawmakers - some of the most liberal and conservative - will roll out a slate of specific legislative proposals with broad and surprising support across the ideological spectrum. Odd couples like Representatives Cory Gardner, the Colorado Republican who was swept to the House in the 2010 Tea Party wave, and Peter Welch, a liberal Democrat from Vermont, will team on actual legislation, not statements of ideals, colored lapel ribbons or promises to sit together at State of the Union addresses. Senators who embraced Tuesday's agreement to call off filibusters of executive-branch nominees promised this week to extend the spirit of compromise to more whole-Senate gatherings, retreats, budget negotiations and other vexing legislative matters. Seven senators, four Democrats and three Republicans, unveiled legislation on Wednesday to offer legal protection to journalists ensnared in leak investigations. "As a prosecutor, I don't like to use the word "gang," but it's another big "gang" we have here," said Senator Amy Klobuchar, Democrat of Minnesota. Senator Lindsey Graham, Republican of South Carolina, said a group was forming to try to reverse the automatic across-the-board spending cuts before they do more damage next fiscal year. But beyond those pledges of bonhomie, the institutional impediments to progress remain unchanged, especially in the Senate. Indeed, the deal to head off the filibuster-rule change nearly derailed 24 hours after it was struck when Thomas E. Perez, President Obama's nominee to be labor secretary, squeaked past a Senate filibuster by a single vote on Wednesday afternoon, 60 to 40. The Republican Senators John McCain of Arizona, the architect of the filibuster deal; Lamar Alexander and Bob Corker of Tennessee; Mark Steven Kirk of Illinois; and Lisa Murkowski of Alaska saved the nominee - and the supposedly growing spirit of bipartisanship. "Right now the only people who are empowered are the obstructionists," said Senator Mary L. Landrieu, Democrat of Louisiana, who in 2005 joined 13 other senators to thwart an effort to end filibusters of judicial nominees but was ready to back the move to end filibusters of executive nominations this round. "And for the rest of us, the power we should be wielding on behalf of our constituents is virtually nil," she said. Since Democrats began threatening action to neuter the filibuster, critics have warned that simple majority votes in the Senate would make that chamber like the House, where the majority rules absolutely. But with a 60-vote threshold in the Senate, the minority party tends to rule absolutely on any issue lacking overwhelming bipartisan support. That is because only the largest gang can muster 60 votes, and a premium is placed on leadership loyalty in the minority party.