[John] McCain's selection of Alaska Gov. Sarah Palin gave the GOP ticket a shot of excitement. So, even though McCain's vetting of Palin was cursory, and journalists or Democratic opponents could still uncover something horribly damaging, Palin counts as an asset, at least for now.
But what does that mean for races down the ballot? In part the answer depends on whether you believed that Republicans had a turnout problem before Palin was chosen. There are two schools of thought. The first is that although many Republicans were not excited about McCain, a longtime maverick and, yes, irritant to the GOP establishment, the party's voters would have supported him anyway. They might not have run to the polls, but they would have voted. This theory posits that these voters simply feel better now about a vote they would have cast anyway.
The second theory is that if McCain had not added Palin or someone else capable of revving up the GOP base, quite a few Republicans wouldn't have voted. A moderate case of sniffles, an unusually busy first-Tuesday-after-the-first-Monday-in-November, or any number of other excuses might well have been seized upon. And these Republicans would simply not have felt strongly enough about their support for McCain to persevere and vote. Under this theory, Palin really helps unless her standing is damaged.
Where Palin may not be able to help is among what some Bush campaign strategists in 2004 called "unreliable Republicans," those who would vote Republican but have a history of not showing up on Election Day. These are people who have to be identified and hounded with phone calls and visits to their homes to remind them that, yes, this is Election Day and they are expected to vote. McCain has neither the money nor the organizational ability to match the get-out-the-vote efforts of President Bush's 2004 campaign or Obama's current effort.
So perhaps Palin is an asset but not quite a savior. For down-ballot GOP candidates who need all of the turnout assistance they can get, she will help some -- but probably not enough unless they were already within shouting distance of victory. Republicans won't have the masterful vote-generating machine they've grown accustomed to, but they are better off with Palin near the top of their ticket.