Another sane American in a conservative paper draws the same sane conclusion as Jon Rauch:

People in power simply can't be trusted. If we're going to have a Republican executive branch, we need a Democratic legislature to hold its feet to the fire. And vice-versa.
So on Tuesday, I'm neither voting Democratic or Republican. I'm voting for the oldest party in the republic. Its name never appears on the ballot, but it's always there and it has always served us well. Divided government.

If you're a Republican concerned about national security who still (somehow) believes the Republicans are better at it, your president won't change. But he will be forced out of denial and compelled to face reality. The Democrats, in a divided government, will also have to take responsibility for the hard choices involved in wartime. So divided government is win-win right now.

Vote Democratic next Tuesday, or if you just can't, abstain. For the country's sake - and for the soul of conservatism.