Sens. Marco Rubio (R-Fla.) and Rob Portman (R-Ohio) have a leg up in the GOP veepstakes, the logic goes, because they come from extremely valuable swing states.

Sen. Marco Rubio (R-Fla.). (AP Photo/Alan Diaz, File)

If history has shown us anything, it’s that the home state of a potential vice presidential nominee shouldn’t be over-estimated as a factor in the process. In fact, it’s relatively rare that a presidential nominee picks a running mate from a swing state with an eye toward picking up that state’s electoral votes in November.

Over the last 40 years, only three vice presidential picks (out of 15) have come from legitimately competitive swing states, and the last one came in 1992 when Bill Clinton picked then-Sen.Al Gore and went on to carry Gore’s home state of Tennessee twice. (And Tennessee wasn’t really considered all that much of a swing state back then.)

Before that, the last two swing-state VP nominees were Rep. Geraldine Ferraro (D-N.Y.) in 1984 and Texan George H.W. Bush in 1980, when their states were more competitive than they are today.

Since then, we have seen vice presidents come from some of the least competitive states on the map — Alaska (Sarah Palin), Delaware (Joe Biden), Wyoming (Dick Cheney), Connecticut (Joe Lieberman), New York (Jack Kemp), Indiana (Dan Quayle) and even North Carolina (John Edwards), which wasn’t a swing state when Edwards was put on the Democratic ticket in 2004.

A little further back, it was more common to pick a nominee from a competitive state. But that was back when the national electorate wasn’t nearly as polarized, and there were quite simply a lot more swing states on the map.

(Fun fact: Between 1960 and 1988, only one state went for the same party every year — Arizona — and 33 of 50 states voted at least twice for each party.)

Indeed, it seems exceedingly rare that a presidential candidate has picked a running mate for the express purpose of winning his or her home state. Or at least it’s the exception rather than the rule.

Now, none of this is to say that Rubio and Portman — or even other swing staters like Virginia Gov. Bob McDonnell or Rep. Paul Ryan (Wis.) — won’t get the Republican VP nod. But it does mean that we would all be much better served to look at their personal attributes when surmising what they would bring to the ticket, rather than the abbreviation that follows their name.

And keep in mind: Of the four, only McDonnell has regularly polled an approval rating above 50 percent in his home state. So the idea that any of them would help much in their home states might be a little over-cooked to begin with.

It’s much more likely Romney’s pick will be based on how that candidate helps him win nationwide than in one state — no matter how important that state is. Whatever benefit he gets in Florida, Ohio, Virginia or Wisconsin would simply be a bonus.