The equation, in theory, goes something like this:

If (A) progressive voters favor medical marijuana, and (B) a medical marijuana amendment is now on the November ballot, then (C) the more liberal candidate for governor will benefit.

In other words, this was a good week for Charlie Crist, right?

Nonpresidential elections tend to draw older (theoretically conservative) crowds, so any issue that engages younger voters has to be good for Democrats.

There's just one caveat: This theory hasn't produced overwhelming results elsewhere.

Looking back at 13 states with medical marijuana ballot initiatives in the past 20 years or so, it's hard to say with certainty that any candidate owes victory or defeat to an influx of young voters.

For instance, voters in Montana approved a marijuana amendment in 2004 while electing a Democratic governor for the first time in 20 years. But the Democrat they elected had come out against legalized marijuana. And considering voters also went big for George W. Bush and passed a gay marriage ban, it doesn't look like a liberal avalanche in retrospect.

In 2010, voters in Arizona approved medical marijuana but also elected a Republican governor for the first time in a dozen years.

The story is similar in Washington, Oregon, Alaska, Nevada, Colorado and other states where the coattail effects of pot often seem inconclusive.

So, should we dismiss marijuana's impact in Florida?

Not necessarily.

What could make a difference is if Crist pushes this harder than candidates have in the past in other states. History says just being the Democrat on the ballot will not guarantee him support from marijuana proponents. So Crist might consider making this a wedge issue.

Since Gov. Rick Scott has an improving economy on his side, Crist is going to have to stake out ground elsewhere. Social issues such as medical marijuana and same-sex marriage could help him paint Scott as an out-of-touch conservative in a moderate state.

"Based on the polls, medical marijuana enjoys greater support than either Rick Scott or Crist in Florida," said Morgan Fox, a spokesman for the Marijuana Policy Project in Washington, D.C. "I can't imagine it's the greatest idea for a candidate to be against something so many voters are supporting.

"While we may not see a higher turnout, the medical marijuana question could change the demographics of who does come out."

Proponents of medical marijuana have been on a roll the past couple of weeks, but they can't afford to relax now. That also may help Crist.

Amendments require a 60 percent majority in Florida, and that's not an easy threshold to reach — no matter what the polls say.

Of the last 17 state initiatives involving medical marijuana nationwide, only six have topped 60 percent. Since 2010, the numbers have been 50.1 (Arizona), 37 (South Dakota), 63 (Massachusetts) and 49 (Arkansas).

"A lot of people will say they support something and then don't show up," said Fox. "You generally want polls to show you have 10 percent more than you need. I think the latest polls in Florida are around 77 percent, so I'm pretty confident it will pass. But, yes, it's entirely possible it won't."

It's an issue Crist shouldn't take for granted, either.