Federal politics crossed a threshold somewhere between Tuesday night and Wednesday morning.

This was partly because of the presidential primary results in North Carolina and Indiana, where Sen. Barack Obama (D-Ill.) lengthened his lead and Sen. Hillary Rodham Clinton (D-N.Y.) failed to produce the game-changing results she needed and predicted.

Pundits across the spectrum, including her supporters, came to the conclusion that the race was over and Obama was the inevitable nominee; the Denver convention in August would be a formality, not a fight, as the party hierarchy so fervently hoped.

Clinton clearly does not see it that way — at least not publicly. Her senior campaign officials spread the word Wednesday that she remains “in it to win it.” The candidate sought to woo superdelegates and again pressed the case for Michigan’s and Florida’s delegates to be seated in Denver.

Some lawmakers have, however, reached the foot-shuffling, don’t-look-her-in-the-eye phase of acceptance that Clinton is done. Maybe they and most other people are wrong, and the candidate is right. We won’t be waiting long to find out.

But it was not just the Democratic primary that conveyed federal politics into a new era. Sen. John McCain (Ariz.), the Republican candidate, has seen his recent poll gains against Obama and Clinton eroding. And in North Carolina, despite having no opponent, 27 percent of Republican voters opposed him. GOP optimism about McCain’s chances has grown since he clinched the nomination in March, but we’d bet that this dips again in polls at least in the short term.

Finally, a new era arrived also on Capitol Hill. Dispirited Republicans, looking ahead to an apparently inevitable drubbing in November, have started to edge away from President Bush. It might become a panicky stampede.

Sen. Saxby Chambliss (R-Ga.) plans to try gathering support to override a veto of the farm bill, should it come; many Republicans seemed certain to cross the aisle last night to vote for Rep. Barney Frank’s (D-Mass.) housing bill despite White House opposition; it’s a fair bet, too, that fearful Republicans will also defy Bush and vote for the House Democrats’ supplementary war spending bill, despite the fact that it is laden with tens of billions of dollars of extra spending.

Members of the GOP, terrified of what November will bring, less than delighted with their presidential nominee, fearful that voters are in a mood to exact a second cycle of punishment, are scrambling and scurrying for safety.

A roar of incipient victory has been gathering in the throats of the left for months. Nemesis, following swiftly on the heels of hubris, has punished premature triumphalism before, and that classical sequence should always prompt caution.

But right now, there is little to hold back Democratic glee.