The polls all predict disaster for the Republicans, and everybody from the mainstream media to conservative commenters and bloggers seems to believe them. It’s a done deal. Glenn Reynolds even offered a much-discussed "pre-mortem" explaining all the reasons (and they’re good ones!) why voters are likely to punish the Republicans severely come November (see also Glenn’s follow-up).

Prognosticators are so certain of a crushing GOP defeat that the Washington Post seemed genuinely puzzled that this belief isn’t shared by the White House:

Amid widespread panic in the Republican establishment about the coming midterm elections, there are two people whose confidence about GOP prospects strikes even their closest allies as almost inexplicably upbeat: President Bush and his top political adviser, Karl Rove.
…

The question is whether this is a case of justified confidence — based on Bush’s and Rove’s electoral record and knowledge of the money, technology and other assets at their command — or of self-delusion. Even many Republicans suspect the latter. …

Today in The Corner, Rich Lowry quoted a White House bulletin that suggested viewing all the recent polling data with skepticism (emphasis in The Corner):

A spate of recent polls paints a very gloomy electoral outlook for GOP candidates in next month’s elections. One reason for that, possibly, is a set of samples in recent polls that do not mirror the historical norm for party ID. A memo circulating among Republicans on the Hill, authored by GOP pollster David Winston, takes a look at the historical spread between Democrats and Republicans in House elections and polling over the last 14 years. According to Winston’s analysis, there is a material discrepancy between the party identification listed by people in exit polls (people who actually voted) between 1992 and 2004, and those used over the last few weeks.

Since 1992, the party ID differentials have ranged from +4% Democratic (1998) to +2% Republican (2002). Winston looked at the October polling samples from 8 different polling organizations. The smallest party ID differential was +5% Democratic by CBS/NYT. CNN didn’t provide party ID data. The other six ranged from +7% Democratic (Pew) to +11% Democratic (Newsweek).

Can you say "wishful thinking"? Or "attempting to create a self-fulfilling prophecy"? I wouldn’t bet against Karl Rove just yet.

My take? Glenn and other critics are absolutely correct regarding the failings, betrayals, malfeasance, and incompetence of far too many congressional Republicans. They richly deserve to be punished. But Rush is right when he says that they may deserve to lose, but we don’t deserve the higher taxes, slowing economy, increased federal spending, decreased national security, and other consequences that are sure to follow if Nancy Pelosi becomes Speaker of the House and Charles Rangel chairs the Ways and Means Committee.

Voters who are pro-free-market, limited-government conservatives or libertarians should exercise some discretion. If you’re looking at a House or Senate race that’s got an absolute shoe-in incumbent of either major party (and that’s most districts), by all means use your vote in a way that sends the best message — vote Libertarian, Constitution, write-in, or not at all (don’t add to a big-government liberal’s vote total for any reason — that sends entirely the wrong message).

But if you’re in a competitive district or state, don’t just blindly punish a less-than-ideal Republican or tell yourself that this particular Democrat’s pretty moderate, doesn’t support tax increases, etc. — helping to elect that Democrat, no matter how decent and harmless, helps to put Harry Reid, Nancy Pelosi, and friends back in control. What do you suppose the consequences will be for taxes, spending, regulation, national security, judgeships, … ?