Barack Obama's victory in the North Carolina primary was actually the second important election result for his campaign this month.

The first, which has not received enough notice, was the triumph of Louisiana Democrat Don Cazayoux in the race for an open U.S. House seat despite an aggressive Republican campaign to link the moderate Cajun to Mr. Obama, liberalism and high taxes.

That the Obama link did not bring down Mr. Cazayoux in a district that voted 59 percent for George W. Bush in 2004 will help reassure Democratic superdelegates from Republican-leaning districts that they can live with Mr. Obama at the top of their party's ticket.

And the failure of old GOP tactics of liberalism-by-association and taxophobia was "a sharp wake-up call for Republicans," in the view of no less an authority than former House Speaker Newt Gingrich.

In an important manifesto published this week in the conservative magazine Human Events, Mr. Gingrich warned that "the Republican brand has been so badly damaged that if Republicans try to run an anti-Obama, anti-Rev. Wright, or (if Sen. Clinton wins), anti-Clinton campaign, they are simply going to fail."

Significantly, Mr. Gingrich argued that the Republican Party's weakness could "ultimately outweigh" the "personal appeal" of presumptive Republican nominee John McCain and "drag his candidacy into defeat."

Mr. Obama's strong showing in North Carolina and his near-win in Indiana not only blocked any obvious path to nomination left for Hillary Clinton but also marked the emergence -- after a long, listless and lackluster interval -- of an Obama prepared to fight back against precisely the campaign he will confront from the Republicans.

In his speech Tuesday night, Mr. Obama predicted that his opponents would "play on our fears and exploit our differences." He would face "the same names and labels they always pin on everyone who doesn't agree with all their ideas, the same efforts to distract us from the issues that affect our lives, by pouncing on every gaffe and association and fake controversy, in the hopes that the media will play along." And then he promised "to make this year different."

Many Democrats still worry that this will be harder for Mr. Obama than he makes it sound. Several party insiders acknowledged that Republicans are far less intimidated by the prospects of facing Mr. Obama than they once were.

They know that Mrs. Clinton's campaign located the seams of division inside the Democratic electorate, and that Mr. McCain will be able to run a two-level campaign. His attacks on Mr. Obama can be subtle while groups theoretically independent of his campaign can do the real damage.

Mr. McCain's first advertisement directed to the general election presented him as "the American president Americans have been waiting for."

What message was he sending with that slogan, unveiled in late March? If Mr. McCain would be the "American" president, what was he implying about a possible opponent with an African first and last name and an Arabic middle name? Those implications will be fully laid out by Mr. McCain's allies.

Yet the campaign run by Mr. Cazayoux (it's pronounced Caj-u, as an ad starring his young daughters taught the voters of Louisiana's 6th District) suggested that Mr. Obama may be right about old attacks no longer working.

In a district that Republicans had held for 33 years, the party and its candidate Woody Jenkins ran a campaign straight from their tattered playbook. Republicans tried to persuade voters that Mr. Cazayoux was really pronounced "Tax You" and were unrelenting in trying to tie Mr. Cazayoux to Mr. Obama and the Democratic House speaker.

"A Vote for Don Cazayoux is a vote for Barack Obama and Nancy Pelosi," one ad declared. "If Don Tax You gets to Washington, he'll do what they tell him to do." Another ad cast the stakes this way: "Is Obama right for Louisiana? Is Pelosi? You decide."

Decide the voters did, not so much for Mr. Obama and Mr. Pelosi as against the very concept of the Republican campaign. Mr. Cazayoux ran as a conservative on guns and abortion, but relied on national Democratic themes in advocating for "middle-class families" and the proposition that "every family should have health care."

Mr. Cazayoux's victory is one sign that the issues this year are moving the Democrats' way. Mr. McCain's failure to gain a clear lead on Mr. Obama or Mrs. Clinton is another. "Without change we could face a catastrophic election this fall," Mr. Gingrich declared of the Republicans' chances.

At least when it comes to assessing this year's political terrain, Newt Gingrich and Barack Obama are on the same page.