Here's a thought exercise for you for you: If a GOP congressional candidate has never met Donald Trump, how can Democrats air an attack ad of him shaking Trump's hand?

The first response that comes to mind -- for me at least -- is: Photoshop. And that's exactly what House Democrats' campaign arm did when they superimposed Rep. David Jolly's (R-Fla.) head over an image of another white guy shaking Trump's hand.

But is that even legal? Jolly, who is in a competitive reelection battle with former Gov. Charlie Crist (D), doesn't think so. As The Tampa Bay Times reports, he looked up at the TV while at a fundraiser Tuesday night, saw an image of him "shaking hands" with Trump, and threatened to sue the TV stations running it if they don't take it down.

"Not only have I never met Donald Trump," Jolly told the Times' Charlie Frago. "I don't own a red-and-white striped tie."

It's true you can't just run a political ad claiming something happened that didn't. The ad couldn't say, like, "Jolly says he'll vote for Trump," because Jolly has actually said he won't vote for Trump.

But you can exaggerate something that might happen to prove a point, political ad experts tell me.

The key is to make sure what you're dramatizing doesn't pass the believability test: Would a reasonable person actually think this is true? If so, media law says you've taken too much liberty with something.

If a reasonable person can tell it's fake, you're probably good to go. And in general, the courts have given political ad makers wide latitude to dramatize things.

Let's take the Jolly example. Do you watch this and think he actually shook hands with Trump?

Believability is in the eye of the beholder. But ad experts point out to me that the image of them "meeting" has the word "Dramatization" underneath it.

And the entire ad is framed as a "What if" scenario, asking viewers to "imagine" a Donald Trump presidency. If you're to follow the ad's logic, under that scenario, Jolly might be shaking hands with the president because he's a Republican and so is Trump. And here's what such a handshake would look like.

Jolly's lawyers don't see it this way. The Tampa Bay Times' Frago reports Jolly's attorney wrote a letter to Tampa NBC affiliate WFLA demanding they stop running the ad, calling it misleading and "patently false."

No word on whether the TV station has dropped it. Jolly is one of House Republicans' most endangered incumbents in 2016. He's in a seat redistricted to lean left, and he's burned bridges with the establishment in his party after he criticized it for its fundraising demands in a "60 Minutes" segment. Which means that while Democratic groups are pouring in more than a million to help Crist -- and run ads like the one in question -- Jolly can't count on the same firepower to fight back at an ad he hates.

And given what we know about media law, it's also not clear whether Jolly can effectively sue a TV station over it either.