Correction: An earlier version of this post incorrectly referred to a television commercial. It should have said radio commercial. This version has been updated.

As John F. Kennedy once said, “sometimes party loyalty asks too much.” In Virginia’s 7th Congressional District race, Democrats are not fielding a candidate. This means the winner will be the Republican whom Democrats dislike the most — House Majority Leader Eric Cantor — or his challenger, the seemingly nondescript college professor David Brat.

Cantor’s campaign against Brat has been disappointing even by Washington’s cynical standards. For example, Cantor is using a pathetic play to claim Brat has liberal Democratic associations. The truth is the good professor is a conventional conservative eagerly seeking tea party backing.

We find Cantor’s campaign tactics troubling.

The best you can say about Professor Brat is that he is a novice running on a shoe-string budget and not aware of those operating in his name. Even seasoned campaigners often fail to properly vet staffers and supporters at times. So we have tried over the previous months to give Brat the benefit of the doubt given his virgin status. But as the campaign comes to a close, we are reminded of the Southern political adage: If it walks like a duck, quacks like duck and looks like a duck, then it is what is.

We have learned that the narrator of a radio commercial supporting Brat is someone whose political views are extreme even by today’s unhinged rhetoric. Moreover he doesn’t hide it, but expresses them through a Facebook page. We recognize that social media is sometimes where people talk before they think and even try to be provocative for its own sake. This is our digital world, unfortunately.

But, at this point, it impossible to give Brat amnesty on this subject, especially given his political views on personal responsibility in connection with other issues. Given our politics, Brat isn’t responsible for how people vote. In the United States, like it or not, everyone gets to cast his or her ballot in private, for his or her own reasons — good, bad or ugly.

That said, this doesn’t allow Brat to be seen as encouraging or benefitting from such votes. He has a responsibility to do the opposite. This responsibility was mostly famously exercised in Virginia by 1985 Democratic lieutenant governor candidate Doug Wilder. At the time, he was 20 points behind in his effort to become the first African American elected statewide in the South. A Virginia Republican, who happened be African American, announced that he and other black Republicans should jump party lines to back Wilder. Wilder immediately rejected any such support, saying Americans believe we should be judged on merit.

We understand Professor Brat is being badly outspent and is facing unfair attack. But this circumstance does not excuse his surrounding himself with people who would ruin our freedoms in the name of protecting them. The good professor has shown irresponsibly bad judgment in allowing such a person to in effect be his spokesman through the narration of his radio ad.

He has crossed the line. In our view then, responsible Virginians, even Democrats, may have an obligation to vote for Cantor on Tuesday to make sure Brat’s politics are rejected.

We are not so naive as to fail to see that Democrats might reject the notion of a responsibility to vote for Cantor, their political antagonist. But as the late President Kennedy said, sometimes the greater good will require a Democrat to back a Republican.

Norman Leahy is an editor of the conservative Web site and producer of the political radio show “The Score.” Paul Goldman is a former chairman of the Democratic Party of Virginia. They are blogging together on All Opinions Are Local during Virginia’s 2014 General Assembly session.