A Bush-Rubio ticket? Improbable but not impossible.

Former Gov. Jeb Bush and Sen. Marco Rubio are both from Florida and could make for an effective GOP ticket. But the Constitution makes things tricky.

When political handicappers blue-sky about the 2016 GOP presidential ticket, they generally rule out an all-Florida ticket – former Gov. Jeb Bush and Sen. Marco Rubio. There are constitutional reasons that make it complicated but not impossible. And in some ways, a Bush-Rubio ticket may make sense.

Let’s start with the positives: In a competitive presidential race, the Republicans cannot win without winning Florida. It’s the third most populous state in the country, with 29 electoral votes. It’s also the biggest battleground state.

So if you absolutely need Florida, why not double down on “Florida-ness”?

Second, both Mr. Bush and Senator Rubio are embedded in the Hispanic community and fluent in Spanish. Bush’s wife is Mexican-born and Rubio is the son of Cuban immigrants. The Latino vote is crucial in 2016, and the GOP needs to up its game dramatically to win enough of that demographic (upwards of 40 percent) to win the White House.

Third, they represent age diversity. With Bush, in his early 60s, at the top of the ticket, you get gravitas. Rubio as running mate, almost 20 years younger, brings the next generation into national leadership.

Fourth, they’re old friends. Bush has long been Rubio’s mentor, before and including Rubio’s run for the Senate in 2010. And even though they’re now competitors (assuming Bush gets into the race soon),  they’re still friendly. They recently sat next to each other on a flight back to Miami, and reportedly chatted amiably, even as Rubio worked on his announcement speech.

On the negative side, there’s the constitutional matter.

Contrary to popular belief, the United States Constitution does not ban two people from the same state from running on one presidential ticket. But it does make life complicated for that state’s electors. Under the 12th Amendment, each member of the Electoral College – the people who actually vote for president and vice president – must vote for at least one candidate who is not an inhabitant of that elector’s state.

So in 2000, when former Defense Secretary Dick Cheney prepared to join the Republican ticket with then-Texas Gov. George W. Bush, he changed his residency from Texas to his native Wyoming, where he already owned a home. Problem solved.

Bush and Rubio don’t have such an easy out. Bush has lived in Florida for decades; Rubio has lived there pretty much his whole life. One of them can’t just up and “move.”

And the Republican Party can hardly afford to forgo Florida’s 29 electoral votes. (After all, that would negate the whole reason for setting up an all-Florida ticket in the first place.) But it wouldn’t have to. As Tim Carney explains in The Washington Examiner, there’s a way to pull that off, though it’s a little tricky.

“Specifically, none of Florida's 29 electors could cast a Bush-Rubio ballot,” Mr. Carney writes.

But there’s another way to make it work. Carney explains:

“First, imagine Bush-Rubio win what [GOP nominee Mitt] Romney won in 2012 plus the six closest Obama states – Florida, Ohio, New Hampshire, Colorado, Iowa, and Virginia. Normally, that would be enough for 285 electoral votes (270 needed to win). But Florida's 29 electors are constrained, so, for a second, take them off the scoreboard. Here's what you're looking at:

“The GOP ticket would have 256 votes pre-Florida. So, 15 of Florida's electors vote Bush-[BLANK] or Bush-Ryan, it doesn't matter. The other 14 of Florida's electors vote [BLANK]-Rubio, or Boehner-Rubio, it doesn't matter. Bush would walk away with 271 electoral votes for President, and Rubio would have 270 for VP. Victory.

“Here's one way of putting it: A Bush-Rubio ticket would need to ‘win’ 285 electoral votes in order to win in the Electoral College. The generalized way of putting it: if both members of a ticket are from the same state and they win their home state, their Election Day margin of victory must be equal to their state's electors, divided by two.”

If Bush wins the Republican nomination, might he actually go down this path? It seems unlikely. He may well want to choose someone from a different part of the country, say, Wisconsin Gov. Scott Walker. Businesswoman Carly Fiorina would bring gender diversity. Louisiana Gov. Bobby Jindal and neurosurgeon Ben Carson would bring ethnic and racial diversity. Maybe he would go for someone who didn’t run for the presidential nomination, as Mr. Romney did.

Much will depend on how each of these people perform as candidates. And Bush is hardly a lock for the nomination. So we’re getting way ahead of ourselves. But having two potentially strong candidates from the same vote-rich battleground state is unusual, and so this idea of a one-state ticket rarely comes up. But at this early stage of the 2016 campaign, it’s at least a live question.