Ohio Republican Sen. Rob Portman announced Tuesday morning that he would forego a presidential bid in 2016 in order to run for reelection.  “With the new Republican majority, I see a real opportunity over the next two years to break the gridlock in Washington and actually get things done to help Ohioans and all Americans," he said in a statement announcing the decision. "That's where I believe I can play the most constructive role. I don't think I can run for president and be an effective senator at the same time."

That's the right call by Portman -- but not necessarily for the reasons he outlined. (Also on Tuesday, Kentucky Sen. Rand Paul, who is going to run for president, announced he is seeking reelection to the Senate too.) The truth of the matter is that Portman's odds of being the 2016 presidential nominee were hovering in that space between "very very slim" and "absolutely none at all".  And, it's not because Portman is too moderate -- he supports same sex marriage and is generally a centrist in terms of his legislative approach. It's because he's a governance guy, not a campaign guy.

The truth of politics is that it is largely split into two camps: People who are good at the governance side of things and those who are good at the campaign side. The lines are not absolute, of course, and, on rare occasions the country produces a politician who can do both at a very high level. (For Democrats, that's Bill Clinton. For Republicans, it's Ronald Reagan.)

The governance people tend to be efficient and effective managers, usually quiet types who are smart operators that everyone wants on their team.  The campaign people are the charismatic ones, less versed (typically) in policy and management but able to inspire and lead through the force of their personality and their rhetoric.  If you think hard enough about it (and, in truth, you don't even need to think that hard) you can divvy up almost every politician currently on the national stage into one of those two groups.

Take the Republican field. Jeb Bush is the governance type. Rand Paul, Ted Cruz and Marco Rubio are the campaign type.  (Just to reiterate: This does not mean that Jeb is ALL governance or Rubio or Rand are ALL campaign.  But, if you had to push them into one of the two categories, those are the ones where they most naturally fit.)

Portman is one of the best "governance" types in recent memory.  Look at his resume: 12 years in the U.S. House, head of the Office of Management and Budge, U.S. Trade Representative, Senator.  Packed into that resume is Portman's status as the guy-who-plays-Barack-Obama-in-mock-debates and his time in the 2014 election as the chief fundraiser for the National Republican Senatorial Committee.

The guy -- whether you agree or disagree with his politics or not -- is demonstrably hyper-competent. During his relatively brief period as a potential 2016 candidate, I talked to several Democrats who acknowledged that Portman would likely be a solid president -- ideology aside. (They also all noted, correctly, that Portman could never win an open primary contest to be the party's nominee.)

Portman's problem is that being a measured, reasonable legislator who excels in the sort of deal-making that was once the lifeblood of Congress is not exactly the stuff of inspirational stump speeches in Iowa. Or the kind of thing that fires up base conservatives in New Hampshire or South Carolina.

We elect campaigners president more often than not.  Take 2012.  Mitt Romney, in his heart of hearts, was a governance guy. He liked taking over big organizations -- the Winter Olympics, for one -- and figuring out ways large and small to make them better. But, he was in a campaign -- one in which he was badly outmatched by President Obama, who is more a campaign guy than a governing one. (Obama's predecessor, George W. Bush, was a campaign guy too.)  Romney's awkwardness as a candidate was made even starker by Obama's ease on the trail.

That we are amazed when the campaign types we elect are, more often than not, less skilled at governance than they were at campaigning speaks to our tremendously short collective memory and our tendency to prize style over -- or at least equal to -- substance.

Portman is on the far end of the governance/substance side of the politicians' continuum.  And so, he never really had a chance at getting elected president in 2016.  That he was smart enough to see that reinforces his uber-governance credentials.