In a piece about Marco Rubio's side gig as a professor at Florida International University, WaPo's Ben Terris quotes an exchange between the Florida senator and a student that is deeply instructive about his understanding of how you run for (and win) the presidency. Here it is:

“The personality of the candidates themselves is so important,” Rubio continues. “It’s an unquantifiable quality that people look at you and say, ‘I’m voting for so-and-so because there is something about him that I like.’­­ ”
A student raises her hand and asks: “Do we spend too much time looking at a politician’s character rather than the actual issues?”
“I don’t know if it should be that way or not,” he says. “But it is.”

Some people might hate that Rubio's right, but he is.

There is a tendency to believe that the average undecided voter in 2012 made his or her mind up this way: They went to the Web site of President Obama, clicked on the "issues" section and put check marks next to all of the policy proposals where they agreed with the incumbent. Then they did the same with Mitt Romney. And they voted for whichever candidate got more checks.

Are there some people who decide that way -- a detailed issue-by-issue analysis of the candidates' positions? Absolutely. And there are also people who vote on how a candidate stands on a single issue -- abortion, immigration, education, etc.

But those people tend not to be the ones who decide elections. The vote for president is the least issue-based -- and the most personality-dominated -- ballot any voter typically casts. It's, for most people, a "feel" vote. The old cliche is that people vote for president based on which of the two candidates they are comfortable with having in their living rooms (metaphorically speaking). I'd modify that slightly to say that people vote for president based on who they believe "gets" them in some way; a candidate who understands their hopes, worries, dreams and concerns.

Look at exit polling from the last two elections. In 2012, Barack Obama beat Mitt Romney 81 percent to 18 percent -- not a typo! -- among voters who said the most important trait in a candidate was that he "cares about people like me." Four years earlier, 44 percent of the electorate said Obama was "in touch with people like you" while just 26 percent said the same of Arizona Sen. John McCain.

Putting aside the numbers, the personality-over-issues reality still comes in loud and clear. What issue won Barack Obama the presidency in 2008 -- in either the primary or the general election? Yes, his initial opposition to the war in Iraq mattered. And, yes, McCain's out-of-touch comments about the relative health of the economy mattered. But, if you had to summarize the 2008 election in a word (or two), you would likely choose "hope" and/or "change." Both of those words deal with a feeling or an idea, not a policy prescription.

Obama won, in large part, because his resume (and his life) embodied the idea of "change" at a time when voters -- Democrats, independents and even many Republicans -- badly wanted to go in a different direction. McCain never really had a chance -- not because of his positions on Iraq or the economy, in particular, but rather because he was perceived as the old way of doing things, a status quo people wanted to reject.

The 2004 presidential election is similarly instructive. If the race between President George W. Bush and Massachusetts Sen. John F. Kerry was decided by the checkmarks-by-the-issues-you-agree-with template I outlined above, Kerry would have won. A decorated military veteran at a time when support for both Bush and the war in Iraq was fading. A deep record and resume on policy issues at a time when confidence in Bush's ability and/or willingness to effectively do the job was rapidly waning.

And yet, Bush won. Why?  Because the incumbent president effectively portrayed Kerry as a windsurfing, Swiss-on-your-cheesesteak ordering, French speaking, "I voted for it before I voted against it, flip-flopping machine. People might not have loved Bush, but they identified with him in a way that they didn't with Kerry. Kerry was other; he was too exotic for people to vote for. (Obama's campaign did a similar thing to Romney in 2012; they cast him as the Mr. Moneybags plutocrat who couldn't care less about what average people did or said at a time when economic anxiety was a very real thing.)

Rubio's insight above then is important -- particularly if he decides to run for president in 2016. (He certainly seems to be leaning that way.) The reality is that in the coming Republican primary, there won't be massive differences between where the candidates land on a variety of issues. (Yes, Jeb Bush will be more liberal than Ted Cruz on immigration and Common Core. But the bulk of Bush's record is quite conservative -- which is true for the entirety of the GOP field.)  So, what will distinguish a candidate in a field that could balloon to 20 (or more)? Personality and perception.

If Rubio can cast himself as a fresh face with a new approach for what it means to be a Republican -- a definite possibility given his relative youth (he's 43) and his Hispanic heritage -- that, much more than any issue position he stakes out, could be the key to emerging as his party's nominee in 2016. He understands that. Which is a big part of the battle.