Like it or not, this truism is very true: Being president in the modern era requires a certain "It Factor."

You don't need star power to make it to the U.S. Senate, or to rise in its leadership. (Looking at you, Senators Reid and McConnell.) You don't need an almost celebrity-like sexiness to succeed in the House. (Who among us would describe Steny Hoyer or Steve Scalise in such terms?) But when we're talking about the presidency, it's not enough these days to be a highly intelligent lawmaker with a history of policy expertise and success. You've got to have charisma. You've got to have charm. You've got to have, well, It.

Now, the fact that we call It "It" implies that this certain something is a little squishy and difficult to define. You just know It when you see It. Still, there are some obvious components. Good looks certainly help. So does confidence. Gravitas, swagger — both help you have It. And it's often very important to be cool — whatever that is. Competence and the notion that you're a winner who can get things done? Now that's It.

JFK had It. Reagan had It. Clinton had It. So did George W. Bush. And Obama — well, let's just say he was once heralded as "the biggest celebrity in the world."

Now of course, some modern presidents lacked this quality, most notably Richard Nixon. You could say the same of George H.W. Bush — though he certainly had It more than his Democratic opponent, noted tank operator Michael Dukakis.

But let's accept for a moment that for better or worse, our celebrity-obsessed, always-on, evermore-demanding, digitally connected culture now requires our president to have It. There are obvious drawbacks to this — the commander-in-chief of the world's most powerful army needs restraint and ideological clarity more than a high Q rating. But it's not all bad. Charisma and confidence and likability matter. After all, the job is at least in part about persuading the public to follow you. Winston Churchill didn't have movie star looks, but he had It. And that charisma and panache helped him pull Great Britain through the darkest days of World War II.

Whether or not the political It Factor is a positive phenomenon for humanity, it certainly seems to be an observable one. As such, it's altogether reasonable for political analysts and commentators to factor this "It Factor" into their electoral predictions.

But in a world where statistical analysis is increasingly utilized and fetishized, the notion that you can make predictions based on intangible qualities makes you seem sort of like the old fuddy-duddy scouts in Moneyball, who would base a player's potential on ungraspable and unquantifiable qualities like "heart."

Whether it's sports or politics, intangibles aren't enough on their own. They are necessary but not sufficient. Sarah Palin, Michele Bachmann, and Herman Cain are all incredibly talented — they all had It — but all lacked some basic policy fundamentals, which prevented them from ever being true presidential contenders.

Still, the It Factor is so important that a candidate with a great resume won't be able to overcome an insufficiency of It. Think Tim Pawlenty or Mitch Daniels.

So who has It in 2016? Chris Christie has It. So do Ted Cruz and Marco Rubio (though Rubio's confidence seems shaken by his immigration failure).

Rick Perry kind of has It — at least in the swagger and likability department. But his lack of gravitas, composure, and policy competence was a real problem in 2012.

Mike Pence and Rand Paul? They're very solid candidates. But neither ooze It.

And then there's Bobby Jindal — perhaps the would-be GOP candidate with the best resume — and Scott Walker. Neither has anything close to It.

On the Democratic side, I must concede that the all-but-certain nominee, Hillary Clinton, has It. Now, she doesn't have It the way her husband does — but really, who does?

Think of the last several presidential elections — Obama over Romney, Obama over McCain, Bush over Kerry, Bush over Gore, Clinton over Dole, Clinton over Bush, Bush over Dukakis, and so on. The candidate who has more of It always wins. So my fellow conservatives, I urge you: We've gotta find a candidate who has It. Because we'll need It in 2016.