It’s time to recover the word my mother taught me never to say: “Stupid.”

There’s a huge difference between ignorance and stupidity. Ignorance is when you don’t know; stupidity is when you do and pretend that you don’t, or when you act as though you do but really don’t.

If my mother had lived long enough to hear comedians Bill Maher and Lewis Black, I think even she would agree with them that we need to put the word back in the American vocabulary. So would St. Thomas Aquinas, who wrote that “willful ignorance” in matters of faith is the greatest of sins.

Interviewing a former White House staff person who understands the complexities of the economy and the debt-ceiling crisis, Bill Maher asked, “Aren’t we just getting more stupid?” He was referring to the readiness of the American people to swallow information that they know isn’t true, or to swallow what they would like to be true but should know isn’t. Lewis Black, commenting on political candidates who skew the facts, yelled, “You can’t just make [stuff] up! You can’t do that!”

But we can and we do. Stupid is in vogue. And, whenever stupid is in vogue, demagoguery takes center stage. Stupid doesn’t like complexity. Stupid wants it simple. Stupid wants reality in short sentences, slogans and code words; it gets angry when facts and other views challenge what stupid has made up. Stupid will swallow poison if it looks like a Hershey’s Kiss. Stupid lives under the spell of ideology.

The recent Iowa presidential debate offered an example of the struggle between willful ignorance and knowledge. Rick Santorum declared that “Iran is a country that has been at war with us since 1979” (when the Iran hostage crisis began), and that we need to use every means necessary to stop the development of an Iranian nuclear weapon. “The senator is wrong on his history,” said Ron Paul, one of the opposing candidates. “We’ve been at war in Iran for a lot longer than ‘79. We started it in 1953 when we sent in a coup and installed the shah.” Santorum shook his head in disgust at Paul’s reference to historical fact. Was he showing disagreement, ignorance, or willful ignorance?

The word “stupid” wasn’t used in the Iowa debate, but willful ignorance was on parade more than once, and it will continue to be on the national stage until the American public echoes Lewis Black’s view that you can’t just make stuff up. Ron Paul finished second in the Ames Straw Poll following the Iowa debate, which gives me some hope that knowledge, facts and complex sentences still have a chance in American culture.

My mother wouldn’t like much of Bill Maher’s and Lewis Black’s vocabulary. She also taught me, with limited success, not to curse. But I think she’d agree with Maher and Lewis, on the left, and with Ron Paul and comedian P.J. O’Rourke, on the right, that the word “stupid” should be brought out of mothballs for the very reason that we once put it away: for a return to civility. It may not seem civil to refer to someone as stupid, but it’s more civil than relying on willful ignorance for political advantage.

GORDON STEWART is pastor of Shepherd of the Hill Presbyterian Church in Chaska, Minn., and moderator of First Tuesday Dialogues: Examining Critical Public Issues Locally and Globally. He is a source in Minnesota Public Radio’s Public Insight Network.

This commentary aired Aug. 16, 2011, on Minnesota Public Radio. Used with permission from MPR Network (KNOW 91.1 FM)