Every GOP presidential race needs a Rick Santorum. I don’t mean every race needs him, but someone like him — a long shot, articulate candidate who is able to engage and disarm the charlatans and kooks. A candidate with nothing to lose and no fear of offending potential supporters who might be fond of an opponent is a valuable commodity.

Former Sen. Rick Santorum, R-Pa., poses for a portrait in his publishers office Wednesday, April 23, 2014 in Washington, before an interview about his recently released book titled "Blue Color Conservative." The once and perhaps future presidential candidate has lots of policy ideas for fellow Republicans seeking public office. He's just not sure he’ll be one of those hopefuls ever again. "Yeah, I don’t know if I can do this. It’s just tough," Santorum said about another White House run. In the interview, Santorum said the GOP will struggle to win races unless candidates came up with policies that help working Americans. (AP Photo/J. David Ake)
Former Sen. Rick Santorum in April. (J. David Ake/Associated Press)

In 2012 Santorum ably played this role against former Texas congressman Ron Paul. He challenged his crackpot ideas about Iran, engaged him on the 10th Amendment and repeatedly highlighted where conservatism and libertarianism depart. Santorum didn’t win and Ron Paul was never going to, but Santorum did help shape the debate. He didn’t have to worry about offending Ron Paul voters (he was never going to get them) or taking spears from Paul the Elder. Every duel raised Santorum’s profile and reminded mainstream GOP primary voters how beyond the pale Paul was.

Looking ahead to 2016, it’s not clear whether Santorum will run again and this time take up the cudgel against Sen. Rand Paul (R-Ky.). But you got a hint of what that would be like when Santorum on CNN’s “Crossfire” picked up where he had left the Paul family in 2012:

VAN JONES: . . . . Rand Paul, who now seems to be everywhere, he’s the front-runner in your party. You agree with his ideas? Are you going to support Rand Paul?

SANTORUM: Look, as I said before, there’s diversity in the Republican Party.

JONES: Well, speaking of diversity, now you’ve got Rand Paul. He’s your front-runner. There he is with Rupert Murdoch there at the Kentucky Derby. Is this the new face of the Republican Party? Is this your leader?

SANTORUM: Well, no, he’s not my leader. I can tell you that for sure. But his father and I had some disagreements during the last campaign.

JONES: If a libertarian like him becomes the leader of the Republican Party, gets the nomination, will you vote for him?

SANTORUM: Well, I don’t think that will happen. Because the Republican Party is not a libertarian party. It is a conservative party. And it will nominate a conservative, not a libertarian.

Santorum, if he ran, would no doubt take on Rand Paul’s eccentric historical views and national security positions. (You can imagine him ridiculing everything from Rand Paul’s fixation on droning terrorists at cafes to determination to slash the budget and refusal to rule out containment as an Iran strategy.) As he did in 2012, he would also, I strongly suspect, be more inclined to focus on working-class voters (the subject of his new book) and press the agenda of conservative reformers such as Sen. Mike Lee (R-Utah) — for example, opposing a flat tax that would raise taxes on working Americans and favoring a child tax credit to support families. (Last year Ramesh Ponnuru pointed out that “Paul’s economic plan includes a 17 percent flat tax to replace the current income tax. The effect of such a policy would be a bigger bill for a lot of middle-class households. The median income for a family of four is $65,000, and under the current tax code — assuming the family takes the standard deduction — its federal income-tax bill would be about $2,700. Under the plan Paul sketches, it would be about $3,500. A single mother of one making $35,000 a year would see her tax liability rise, too. If she uses the standard deduction, she pays about $1,500 today. She’d probably pay $2,100 if Paul had his way.”)

If Santorum doesn’t run, Rand Paul’s most obvious interlocutor on foreign policy would be former United Nations Ambassador John Bolton, who has formed a PAC and SuperPAC precisely to combat the sort of isolationism advocated by Rand Paul. If he runs, he’d be among the most able fact-checkers and debunkers on foreign policy; and, as a critic of some of the policies of President George W. Bush and a skeptic of democracy promotion, he would be hard to write off — as Rand Paul does with those who disagree — as just another “neoconservative.”

All of this reminds us that it is important to have a robust and well-rounded field of candidates. It is only in the cauldron of intense debate that the strengths and weaknesses of candidates and their ideas can truly be tested. Republicans horrified at the prospect that those with opposing views — be it on education, immigration or foreign policy — might run reveal a lack of confidence in their views. All interested Republicans with something to say should run; let the cream rise to the top and the indefensible ideas fall by the wayside. Sometimes it is as important which ideas flop as it is which candidate eventually wins.

Jennifer Rubin writes the Right Turn blog for The Post, offering reported opinion from a conservative perspective.