There have been recent signs that the Republicans could bounce back from their devastating defeat last fall in the upcoming midterm elections. As I wrote a month ago, the early signs are that the Democrats may lose ground in the 2010 elections. Now the Washington Post reports that the Democrats are raising substantially less money than they were able to two years ago, in part because large donors have been turned off by the Democrats attempt to regulate big business.

But while the Democrats are likely to lose seats in the House and Senate in 2010, that doesn’t necessarily mean that the Republican Party is about to return to its old prominence. For all the noise generated by “tea party” protests around the country, polls still show that around twice as many people have a favorable view of Democrats as have a favorable view of Republicans.

For years, the traditionally Republican segment of the population has been shrinking. As Michael Grunwald wrote back in May, the American electorate is steadily becoming “less white, less rural, less Christian—in short, less demographically Republican.” And the most conservative group of voters—the elderly—are gradually dying off.

Instead of altering its platform to attract a broader segment of the changing electorate, the Republican Party has purged most of its more moderate members. In the Senate, for example, with the defections of Lincoln Chafee (I-VT) and Arlen Specter (D-PA), Olympia Snowe (R-ME) and Susan Collins (R-ME) are all that remains of the once sizable group of moderate Republicans. And the current stars of the Republican Party—people like Sarah Palin and Liz Cheney—are not likely to win over many moderate swing voters. The Republicans are gambling that a more unified party with a clearer ideological message will be more compelling. Sen. Jim DeMint (R-SC) summed up their strategy when he said that he would “rather have 30 Republicans in the Senate who really believe in principles of limited government, free markets, free people, than to have 60 people who don’t have a set of beliefs.”

The result has been a more energized party, but one with less broad national appeal. Today, as Steve Benen points out, most of the country has a starkly unfavorable view of the Republican Party. For years Republicans won elections pursuing “a southern strategy,” but as a consequence the South is now the only region where more people view the party favorably than unfavorably. As Andrew Sullivan says—repeating a reader’s remark—the Republican Party is in danger of turning into our version of Canada’s Parti Quebecois. It is becoming, in other words, essentially a regional party, which can do little more than voice its protest at the national level.

That’s why the major policy debates right now—like the debate over health care reform—are primarily going on within the Democratic Party. All Republicans can do is disrupt the process from the sidelines in hopes of making the Democrats look bad. The Republican Party has become “the Party of No,” opposing everything as a matter of principle. But that’s not a viable long-term strategy. As long as the Republicans don’t try to reach out to political moderates, they are likely to remain vocal, passionate, and marginal.