It seems too early for an October surprise, but a video taped last October of former Sen. Rick Santorum discussing his opposition to contraception has surfaced, and it could pose serious problems for the surging candidate.

When it comes to discussing such issues, Santorum should have practiced abstinence. He did not.

The problem, of course, is that this now legitimizes what previously seemed to be — despite having been brought up repeatedly during an ABC News/Yahoo! debate — an absurd campaign issue. No matter what anyone said, the recent debate over HHS mandates was patently about religious liberty — not contraception. But now, Santorum’s past comments seem to make the issue fair game — at least, in terms of covering Santorum.

Here’s an excerpt from the October interview:

One of the things I will talk about that no President has talked about before is I think the dangers of contraception in this country, the whole sexual libertine idea. Many in the Christian faith have said, “Well, that’s okay. Contraception’s okay.”

It’s not okay because it’s a license to do things in the sexual realm that is counter to how things are supposed to be.

Santorum is entitled to his beliefs. And certainly, one can admire his willingness to boldly stand up for them. But while this might be a profile in courage, it most certainly is also a profile in bad politics.

His position on contraception is, of course, a minority position — even within the conservative movement.

This doesn’t mean Santorum should have lied or hidden his personal beliefs. If asked, he might have simply said: “The use of contraception is inconsistent with my Catholic faith, but many other fine faith traditions disagree, and I respect their position” — and then moved on.

But Santorum doesn’t really believe that. He was more interested in winning the argument than winning the election.

This was not a mistake or a gaffe. Santorum was fully conscious of the dangers of discussing this issue, even noting during the interview that he’s not “running for preacher,” and confessing: “I know most Presidents don’t talk about those things, and maybe people don’t want us to talk about those things …”

He was right — people really don’t want their president talking about contraceptives.

Interestingly, this insistence on always speaking truth to power — on never backing down — is, perhaps, ironically, Santorum’s political Achilles’ heel (Team Romeny — take notice).

Santorum, it seems, finds it almost dishonorable to parry a question about core values. His candidacy isn’t just about winning, it’s also about sending a message to America. He now has a forum and a microphone — with great power comes great responsibility! — and wouldn’t it would be wrong to pass up this opportunity to teach…or proselytize?

Again, this instinct for stopping to kick every barking dog may make Rick Santorum a very honorable and devout man, but it also most certainly makes him a vulnerable politician. I made almost this exact same point last month when, promptly after a big victory in Iowa, Santorum entered into a debate over gay marriage with a young college student in New Hampshire. (The fact that Santorum continued to stress his cultural conservative beliefs in January — after a strong showing in Iowa — implies that his October comments weren’t merely the product of someone who didn’t really think he had anything to lose by telling the truth.)

Make no mistake, this is an issue he must overcome if he is to be president. He can minimize the damage if he recognizes it in time and confronts it. JFK had a Catholic speech. Barack Obama had a Rev. Wright speech. Mitt Romney had a Mormon speech.

Rick Santorum may need to give a contraception speech.