All of us raging moderates and institutionalists can now breathe a sigh of relief: At least for now, the center holds. In fact, recent developments have finally made clear that a center actually exists in Washington. (Out in the country, there is a large and vibrant center that’s only dimly reflected here in the capital.)

The center’s emergence is clear this week on two issues: the Senate’s compromise on judicial nominations to avert a meltdown on the rules and precedents of the chamber, and the House vote on stem-cell research.

In the former, 14 Senators, including old bulls and newer calves on both sides, superseded their party leaders. In the latter, House moderate Republicans, led by Delaware’s Mike Castle, found a way, for the first time in several years, to assert themselves and prevail against their own party leaders to find a centrist position on a crucial issue of medical research.

A quarter-century ago, most Members of Congress could be broadly characterized as being in the center — ranging inward from at least the 35-yard lines, in a classic bell-curve distribution. Today’s Congress has a pretty barren mid-field area, with far more members hovering around the 10-yard line and a whole lot behind each goal post. It is a classic U-shaped ideological distribution, far more common in a parliamentary system than a presidential one. But the party numbers are close enough that neither end of the spectrum can dominate. Votes from the dwindling number between the 35 yard lines are still crucial.

For several years, the potential has existed for this hardy band to dominate — to forge a new balance of power that requires both sides to negotiate with them. But that potential has gone largely unfulfilled, as partisan and ideological polarization have dominated the landscape in the Clinton and Bush years. The politics have moved beyond party and viewpoint to become almost tribal — and many moderates, when push came to shove, have sided with their tribe, often against their own viewpoints and instincts.

Will this new victory for the center in the Senate now empower and motivate the moderates to assert themselves more often? Will the ability of House moderate Republicans to secure a vote on stem-cell research give them the cojones to buck their party leaders more frequently? I fervently hope so, but I am not wildly optimistic. Why? Start with the Senate, where a robust 14 Senators pulled it together. (And kudos to them all, especially Sens. Ben Nelson (D-Neb.), John Warner (R-Va.) and John McCain (R-Ariz.).)

Conspicuously absent from this group were key figures who should have been there from the get-go, including Sens. Pete Domenici (R-N.M.), Dick Lugar (R-Ind.), Ted Stevens (R-Alaska), Chuck Hagel (R-Neb.) and Gordon Smith (R-Ore.). Domenici, Lugar and Stevens, especially, are three veteran bulls who have nothing to lose by choosing institution over party, and their absence was deeply disappointing.

This truly was a defining issue — one in which the precedent set by overturning a rule by brute majority vote would have done permanent damage to the institutional fabric of the Senate. When Lugar said that, despite his profound unease about what the “nuclear” option would do to the Senate, he would not cross his party leader on this one, it said everything about where our politics has gone in the past several years, and about the limits of the center in this day and age.

The major test ahead for the centrists is, as it has been for so long, our fiscal state of disrepair. Here, fiscal moderation has regularly lost out to party and presidential loyalty. The limiting case here is the PAYGO rule, which has clearly worked to bring fiscal discipline. It would be reinstated by a wide margin in a secret ballot vote, but tax-driven opposition by the GOP’s ideological base — and the failure of moderates to take them on — has kept that from happening. Domenici devoted much of his distinguished career to bringing the United States into fiscal balance and keeping it there. Where was he on PAYGO? And where were the other old bulls who know better?

Another test ahead is free trade. Centrist Democrats who have historically bucked labor and their own party leaders on trade issues are defecting in droves on CAFTA. The economies of the Central American countries are a tiny drop in the ocean compared to ours, making the economic impact of this agreement miniscule for us, yet major for them. The political ramifications for our neighbors are immense, especially when Venezuela’s crazy leader is aiming to be a more muscular Castro intervening in the hemisphere — one with billions in oil revenues to fulfill his radical political ambitions.

Moderate Democrats have a point, that the White House has not talked to them, much less listened to them; in addition, genuine labor and environmental concerns have not been adequately addressed. However, the opposition to CAFTA is taking on those tribal trappings, moving beyond real policy concerns.

As for the moderate Republicans in the House, ethics reform will be the next real test. There will be real, meaningful and balanced reform options on the table, starting with the bill sponsored by Reps. Marty Meehan (D-Mass.) and Rahm Emanuel (D-Ill.), which will be opposed reflexively by the GOP House leaders. (Full disclosure: I offered outside input on the package.) Will moderates do the right thing?

The mobilization of outside groups on both sides on the filibuster issue is a harbinger of things to come — knockdown, drag-out ideological fights on all kinds of matters in Congress, mobilizing opposite bases to all-out warfare. The willingness of House Republican leaders to turn nearly every issue, from the budget to continuity of government, into a partisan battle, is a discouraging sign of the politics of our time. The gang of 14 in the Senate and the Castle crew in the House both show there can be another way. Let’s hope they can coalesce into a real, muscular, permanent center.

Norman Ornstein is a resident scholar at the American Enterprise Institute.