Rick Santorum — in a 2006 interview — said birth control is "harmful to women."

Jennifer Rubin wants you to know:

Now, he qualifies his religious views by saying he doesn’t vote against contraception “because it’s not the taking of a human life” (in other contexts he has emphasized that as a legal matter he has no problem with contraception). But how does that square with his professed belief that a candidate’s values are essential to understanding and predicting his behavior? Perhaps that’s an abortion-only rule.

Watch the video at the link. Santorum says:

"I vote and have supported birth control because it is not the taking of a human life. But I’m not a believer in birth control and — artificial birth control — again, I think it goes down the line of being able to do whatever you want to do without having the responsibility that comes with that.... I think it breaks that … this is from a personal point of view. From a governmental point of view, I support Title 10 (I guess it is) and have voted for contraception — although I don’t think it works. I think it’s harmful to women. I think it’s harmful to our society to have a society that says that sex outside of marriage is something that should be encouraged or tolerated, particularly among the young. And I think it has  it has — and we’ve seen — very, very harmful long-term consequences to a society. So, birth control — to me — enables that and I don’t think it’s a healthy thing for our country.”

I'd like to see the whole transcript — and I will check his 2005 book, which I presume he was talking about. It's pretty clear just from that quote that he wasn't saying what he would do with governmental power. He was speaking "from a personal point of view," expressing the opinion something that people are now free to do isn't good for them and isn't good for society. It's a separate question whether he would deny us this freedom. He would deny us the freedom to have abortions, presumably, because that is "the taking of a human life" and thus important to him "from a governmental point of view."

Should voters worry about what Santorum might do with his personal beliefs if he gets into power? Note that the issue today isn't about banning birth control. It's about subsidies.  What behavior are we incentivizing with government spending? The Obama administration wants to nudge people into using birth control, on the theory that's good policy. Santorum represents the opposite policy position, and not merely because he wants much less government spending. From his book ("It Takes a Family"):

[I]n this country, we continue to pour millions more dollars into comprehensive sex ed, which “protects” against the “effects” of unhealthy behavior, rather than promoting virtue, which will lead to healthy behavior. In 2002, the federal and state governments spent an estimated $1.73 billion on a wide variety of contraception promotion and pregnancy prevention programs. More than a third of that money—$653 million—was spent specifically to fund contraceptive programs for teens. In contrast, programs teaching teens to abstain from sexual activity received only an estimated $144.1 million in 2002. Overall, the government spent 12 dollars to promote contraception for every dollar spent to encourage abstinence. When I have attempted to increase abstinence funding at the expense of contraceptive funding, I have been scolded for “trying to impose religious values on children.” As if telling children to go ahead and have sex all they want as long as they use a condom is not a value statement. It may not be held by many formal religions, but it is certainly held by the materialist philosophy of the left that defends free-sex-and-condoms with religious zeal. If you ever wondered what moral message was being delivered to your children from Uncle Sam—or should I say Uncle Sigmund?—now you know.

Santorum goes on to criticize the Supreme Court for finding a constitutional right to use contraception (even though, he says, if he'd been a legislator, he wouldn't have voted for the law). 

The dissenting justices [in Griswold v. Connecticut] mocked the reasoning of the majority, which in some cases based itself not on the Constitution's text, but rather on the “traditions and [collective] conscience of our people.” How, asked the dissenters, could the Court know the conscience of the people better than legislators? Did not such reliance lead only to the substitution of judges' “personal and private notions” for the decisions of legislatures?...

See? There's that idea of personal beliefs. Santorum doesn't like judges using "personal" views in the development of constitutional law. Of course, the judges — when they talk about the meaning of "liberty" in the Due Process Clause — say that they are finding a "principle of justice... rooted in the traditions and conscience of our people." Justice Black simply didn't think judges could do that.

Santorum's not running for judge, and the Justice Black approach leaves these things to the political branches of government. So, if Black was right, and personal views are going to affect decisions, then we can't get away from the reality that Santorum's personal views will affect his decisionmaking — including whom he will appoint to the Supreme Court, which has the power to reshape our due process rights, perhaps giving a lot more leeway to the political branches of government where Santorum's personal views will affect decisionmaking.