Touch the electrified third rail of a subway system, and you are dead.

In politics, campaign workers try to push their candidate’s opponent onto the "third rail." What constitutes this "third rail" varies from campaign to campaign—from legitimate yet touchy issues like universal health care and Social Security, to more lurid and distracting sideshows. American voters have become used to this tactic. And now it appears in the staid, quiet First Congressional District of Virginia.

Last week, a conservative blogger posted on the internet some rather lewd party photos of Democrat Krystal Ball, who is running an uphill but otherwise proper, let’s-focus-on-the-issues campaign. Everyone has clothes on, and she is with her then-husband, and all the partiers appear to be having a great time; but, they are not the kind of pictures you can print in a family newspaper.

These photos have caused more interest than the otherwise tepid campaign has inspire...