The issue of racial profiling came up in last night’s debate, so let’s take a moment to refresh memories on why this is misguided.

SANTORUM: [O]f course, Abraham Lincoln ran right over civil rights. Why? Because we had a present domestic threat. In the previous wars that we’ve had, we haven’t had this type of threat that we have here in the homeland. And we have to deal with it differently. […]

BLITZER: So just to be precise, is it ethnic profiling, religious profiling? Who would be profiled?

SANTORUM: Well, the folks who are most likely to be committing these crimes. If you look at — I mean, obviously, it was — obviously, Muslims would be — would be someone you’d look at, absolutely. Those are the folks who are — the radical Muslims are the people that are committing these crimes, as we’ve — by and large, as well as younger males. I mean, these are things that — not exclusively — but these are things that you profile to — to find your best — the most likely candidate.

Herman Cain argued along the same lines, calling for “targeted identification.”

CAIN: We can do — we can do — targeted identification. If you take a look at the people who are trying to kill us, it would be easy to figure out exactly what that identification profile looks like.

This argument hasn’t come up in a while, and in case anyone’s forgotten, the line espoused by Santorum and Cain is nonsense.

Indeed, Ron Paul, to his credit, got this just right: “That’s digging a hole for ourselves. What if they look like Timothy McVeigh?”

Right. It’s not at all “easy” to know what a terrorist “looks like.” Some may conclude that anyone with skin darker than a manila envelope should be considered possibly dangerous — and I have no idea how Santorum would recommend telling the difference between Muslim and non-Muslim airline travelers — but using bigotry as the basis for a security policy is not only offensive, it doesn’t work, either.

As Adam Serwer explained a while back, “[R]acial profiling isn’t any more effective than random screening. So rather than making anyone safer, you’re just alienating the communities a former CIA analyst and chief of intelligence analysis for the Department of Homeland Security under the Bush administration has said are themselves ‘the only way’ to really counter domestic radicalization.”

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.