Nothing fires up a crowd like cloture.

Rick Santorum, the man who has improbably become a contender in Tuesday’s Iowa caucuses, was making his closing argument to a sea of TV cameras here on Monday when he swerved into a thicket of Senate trivia.

“I’m not disagreeing with the 17th Amendment,” the former senator from Pennsylvania proclaimed to journalists (and a few locals) at a coffee shop here. But, he went on, that obscure 1913 provision that established the direct election of senators had the side effect of creating “something called cloture.”

All was quiet in the coffee shop. At the senator’s side, a child played with his Game Boy.

It’s not clear why Santorum thought his final pitch to Iowa voters should include a mention of century-old legislative procedure. More clear from the Polk City appearance — and a subsequent one up the road in Perry, Iowa — is that he won’t last long as a top-tier presidential candidate if he doesn’t improve his game.

The “Santorum surge” in recent days has little to do with the candidate himself and everything to do with the fact that he is the last man standing after voters discarded all the rest. There’s little time left to scrutinize Santorum before the Iowa vote — and in his case, that’s an exceedingly lucky thing. Given more time in the spotlight, he would reveal himself as a hard-edged Dan Quayle.

In Perry, Santorum gave his opinion that President Obama was more of a divisive figure than Richard Nixon, keeper of the enemies list: “I suspect President Nixon, although I don’t know, would talk and work with people and wouldn’t go out and demonize them as this president has done.” Santorum doesn’t know it, but that doesn’t stop him from asserting it.

At the same stop, he played loose with the facts when contrasting Ronald Reagan’s vacation schedule with Obama’s.

“I don’t know if it’s true, but somebody told me this,” he began, “that Ronald Reagan never left the White House at Christmas, and the reason was he wanted all the staff to be able to spend that time at home.”

A check of the record would have revealed to Santorum that in 1988, Reagan was in Los Angeles during Christmas, and that he spent the week after nearly every Christmas (and more than a year of his presidency) in Santa Barbara, Calif.

I’ve covered Santorum on and off since his first run for Congress, in 1990, when I was a rookie reporter in Pittsburgh. Months ago, I predicted there would be such a Santorum surge in Iowa. But if and when he receives serious scrutiny, the surge will surely subside.

On Monday, for example, he claimed that he is the only candidate who “has proof that, with a conservative record, they were able to attract independents and Democrats.” And that is why Pennsylvania voters unceremoniously tossed him from office in 2006 by a nearly 18-point margin? A n Iowan reminded him of this.

“Great question,” the candidate replied, blaming his GOP congressional colleagues and President George W. Bush’s unpopularity.

Talking about Obama’s health-care legislation, he pledged that “I simply won’t enforce the law.” But discussing immigration policy minutes later, he said that “we need to enforce the law.”

If the surge sustains him past Iowa, he will have difficulty explaining such things as his pledge to make abortion restrictions his first order of business (never mind that nonsense about jobs) or the treason accusation he hurled at Obama on Monday: In foreign conflicts, he said, “he’s sided with our enemies on almost every single one.”

Scrutiny would also expose Santorum’s attachment to Washington process. His closing argument to Iowa voters moved from his cloture talk to mention of the Senate Appropriations Committee, earmarks, the House Judiciary Committee, the Syrian Accountability Act and a long discourse on Honduras. He grew particularly impassioned when telling his uncomprehending listeners that “we can take the 9th Circuit and divide it into two circuits.”

Santorum is clearly enjoying his surge, boasting that, while other campaigns had an “airplane, bus, cars, etcetera,” he simply had “Chuck’s truck” — a Dodge pickup. Now there is a shiny campaign bus with his name on it.

At Santorum’s first stop, in Polk City, the coffee shop’s maximum occupancy was listed as 49, but at least 200 filled the room and 100 more spilled into the street. In the media throng were journalists from Japan, Russia, France, Britain, Italy and Australia. “They weren’t here last week,” a pleased Santorum told the crowd.

Enjoy it, Senator. They won’t be here for long.