Wolf Blitzer, you boob.

A presidential candidate’s spouse is the ultimate human credential, often the best clue we have about who the aspirant is as a person. Though we sometimes pretend otherwise, a spouse is also a top adviser in her own right (or his), as well as a potential ambassador to the world.

Republican presidential hopeful Mitt Romney listens to his wife Ann introducing him in Jacksonville, Florida, January 26, 2012. (EMMANUEL DUNAND/AFP/GETTY IMAGES)

Yet when CNN’s Blitzer asked the candidates to say something about their spouses at last night’s 19th GOP presidential debate, he did so apologetically, as if we were in for some laughs: “Want to get right back to the rest of the debate,’’ – the important stuff, like colonies on the moon -- he said. “But first, on a lighter subject, I want to ask each of these gentlemen why they think their wife would make a great first lady.”

Texas Congressman Ron Paul appeared uncharacteristically stunned by the question, and did not even mention his wife’s name, which is Carol: “Well, she’s been my wife for 54 years. And we’re going to have an anniversary on February 1. So — but she’s the mother of five of our children.’’ (No, there aren’t more children from another mother.) And she’s a grandmother of 18 grandchildren, does an excellent job. And she’s also the author of a very famous cookbook, “The Ron Paul Cookbook.

Mitt Romney began by vaguely dissing what Paul had said, then vaguely apologizing: “I’ve got to take a little bit more time, a little more seriousness. My — nothing wrong with what you said — I’m sorry.” He, too, neglected to mention the name of said spouse, Ann. But then, unlike Paul, Romney did say what she would bring to the White House – compassion. Because a major knock against Romney is that he often seems to be wondering, “What would a normal person say in a situation like this?’’ his wife’s warmth and experience in dealing with real-world challenges are even more important.

“My wife is also a mom, as I pointed out early on, but in some respects, she is a real champion and a fighter. She was diagnosed in 1998 with multiple sclerosis, and more recently with breast cancer. She has battled both successfully. And as first lady, she will be able to reach out to people who are also struggling and suffering and will be someone who shows compassion and care.”

Newt Gingrich, on trickier ground in introducing his third wife, Callista, handled the question astutely, and even gracefully, by beginning with a bow to his rivals’ wives:

“Let me say, first of all, having gotten to know them, I think all three of the wives represented here would be terrific first ladies. Callista and I have gotten to know all three of them, and we think they’d be fabulous people. So I would rather just talk about why I like Callista, and why I’d like her to be first lady, but she’s not necessarily in any way better. These are wonderful people, and they would be wonderful first ladies.’’

The former House speaker was, as it turned out, the only one of the four GOP candidates who introduced his wife by name.

In the past, Gingrich has described Callista as a cross between Nancy Reagan and Jacqueline Kennedy. First, the Jackie:

“Callista brings a couple of things. One is a tremendous artistic focus. She’s done a video in music education and why it really matters. She’s a pianist by background, plays the French horn in a community band, sings in the choir of the Basilica of the National Shrine of the Immaculate Conception. She really cares about the arts and would bring a really strong feeling for music education and for art and why it matters to people as part of their education.”

Gingrich added: “She’s also very patriotic about American exceptionalism. She’s had a best-selling New York Times book, children’s book.’’ (Isn’t it a little bit elitist to mention that?)

This line, though, is the one you have to love for its baldness: “But — and I, obviously, would be thrilled to be able to hang out with her at the White House. So it would be good.”

Not too surprising, though, it was Rick Santorum, who talks the most about family on the stump, whose intro on his wife trumped all the others.

“Unfortunately, Senator Santorum, your wife is not here tonight,’’ Blitzer said, inviting him to explain.

(Her name, in case you’re curious, is Karen Santorum.)

“Yeah, she’s not,” Santorum said. “She’s doing what she does incredibly well, which is to be a mother to our seven children. And she’s my hero. She’s someone who has been, you know, well-educated. She was a neonatal intensive care nurse for nine years at one of the most advanced nurseries in the country.

“She went on to, because she saw all these ethical challenges there, so she went on and got a law degree so she could — she could deal with those in the — in the legal world,” the former senator from Pennsylvania said. “And then when she got married, she gave that up; she walked away and walked into something that she felt called to do, which was to be a mom and to be a wife.

“And we’ve had eight children. We are blessed to be raising seven. We’ve been through a lot together, losing a child, having a child with a disability that we have now, our little Bella,’’ who has a serious genetic disorder, Trisomy 18. “And the amount of love for these special kids is just palpable in her.

She wrote a book about our son that we lost called ‘Letters to Gabriel,’ about that ordeal that we went through. That book, that little book, has saved countless — I don’t — we know of at least hundreds of lives that were saved because people read that book and realized that the child they we’re carrying had the dignity to be loved and nurtured irrespective of what malady may have befallen that baby in the womb. And so, many children were born and are alive today because of that book.”

Santorum went on: “She’s also written a book on manners. That’s something that I — we have seven children, so we know that kids are not born good. And so, manners is very important in our house. And she wrote a storybook because there were all sorts of how-to books on manners but there was no storybook, teaching manners through, well, how Christ taught us, through stories. And that book has hopefully somewhat civilized some children around this country.’’

After all the heavy stuff, he got a big, relieved laugh with the line about civilizing the little monsties, so the round did end on a “lighter note.’’

And Blitzer approved that message: “Very nice,’’ said he.

Melinda Henneberger is a Post political writer and anchor of ‘She the People.’ Follow her on Twitter at @MelindaDC.