Article in The New York Times sums it up:  A Scandal-Scarred G.O.P. Asks, ‘What Next?’

The basic gist is that the GOP cannot win elections if they alienate the Christian Right.  And this constant drumbeat of sex scandals is alienating the Christian Right.  Here are some select quotes:

Scott Reid, GOP strategist: “The real question for Republicans in Washington is how low can you go, because we are approaching a level of ridiculousness… You can’t make this stuff up. And the impact this is having on the grass-roots around the country is devastating. Republicans think the governing class in Washington are a bunch of buffoons who have total disregard for the principles of the party, the law of the land and the future of the country.”

Tony Perkins, president of the Family Research Council: “Exit polls show that was the No. 1 factor in depressing Republican enthusiasm… There is an expectation that leaders who espouse family values will live by those values. And while the values voters don’t demand perfection, I do believe they want leaders with integrity.”

Now, it’s not like the Christian Right is not going to vote Democratic.  They simply won’t vote.  But without them, the GOP cannot hope to be the majority party.

UPDATE:  This post by Professor Dale Carpenter is spot-on, and makes many of the same points I’ve made.

He basically writes that most Republican politicians are, in fact, NOT anti-gay.  He adds that many Republicans themselves are gay, just like the rest of American.  But the party itself is so beholden to the anti-gay Christian Right (a min9ority, but a powerful minority nonetheless), that it cannot afford to alienate them.  So we get a schism (which amounts, in my estimation, to hypocrisy) wherein Republican politicians feel they must demonstrate (to varying degrees) their anti-gay, "pro-family" creds in order to woo that small but influential bloc of prudes.

Democrats don’t feel this pinch:

This doesn’t happen to the Democrats because the party’s public and private attitudes toward homosexuality are fully consistent: acceptance of gays. Their homosexuals feel little need to remain closeted (with the recent exception of Jim “I am a Gay American” McGreevey). Notably, past sex scandals involving gay Democrats, like Rep. Barney Frank (with a prostitute) and Rep. Gerry Studds (with a congressional page), occurred some two decades ago, when the party was less accepting and the men themselves were still closeted.

He concludes:

The only practical way out of this for the GOP is to come to the point where its homosexuals no longer feel the need to hide. And that won’t happen until the party’s public message is more closely aligned with its private one. That will be the day when the GOP greets its gay supporters the way Larry Craig, with unintended irony, greeted reporters yesterday at his news conference: “Thank you all very much for coming out today.”