Washington shivered in the grip of a cold front last week. In Congress, however, there were hints of an early thaw.

Fresh on the heels of a retreat by Republican House members, who concluded that a debt-ceiling showdown might be a less-than-spiffing idea, Senate Democrats backed off a shaky ultimatum of their own. Majority Leader Harry Reid and Republican leader Mitch McConnell struck an accord to modify the rules for Senate filibusters.

The filibuster has been abused in recent years, and liberals were eager to dynamite the cause of so many Republican- engineered logjams. Instead, the Reid-McConnell deal preserves the power of the minority to require a 60-vote supermajority on legislation. At the same time, the agreement should ease procedural delays and votes on nominations. In return for a slightly smaller jam, Republicans will regain the power, thwarted by Reid, to offer amendments and shape legislation.

For critics of a dysfunctional Capitol, the accord was small beer. Yet for two fiercely partisan leaders, the agreement was nonetheless significant. It represented tacit acknowledgment that Republicans have abused the filibuster, that Democrats have squelched Republican prerogatives and, most important, that neither leader is eager to inflict additional damage on the Senate in pursuit of short-term partisan gain.

The deal was further evidence that in the absence of grand bargains, incrementalism looks pretty grand. The two parties have made genuine progress. The fiscal cliff was averted. The tax burden was adjusted, the deficit trimmed. Chances for additional reductions are good. Meanwhile, a bipartisan group in the Senate is negotiating immigration reform.

If Washington's chroniclers haven't applauded, the markets have. Washington could do worse than its current trajectory.