Rep. Darrell Issa (R-Calif.) was photographed atop the roof of his district office in Vista, Calif. on May 30. (Peter Stevenson/The Washington Post)

Photos and video emerged Tuesday of Rep. Darrell Issa (R-Calif.) standing on top of a roof as protesters chanted “Shame on Issa!” below. A narrative quickly emerged — nudged along by his 2018 opponent — that Issa was hiding from constituents on the roof. But was he?

Let's start from the beginning. Issa's 2018 opponent, Mike Levin, a California lawyer, said in an interview on Tuesday that the protesters rally across the street from Issa's Vista, Calif., district office each Tuesday.

“I don't even like calling them protesters,” Levin said. “They're constituents of Issa, and they're fed up.”

Levin said one protester offered Issa a plate of toast — an apparent attempt to say, “You're toast in 2018.”

Issa subsequently went inside the building, according to Levin. A few minutes later, he emerged on the roof. Levin took a photo and tweeted it out, with a caption that said Issa was “too afraid to come speak with assembled constituents below.”

“I looked up there, and there he was, and within seconds, my instinct was to take a picture,” Levin said. “People were kind of blown away that he was up there, and eventually he walked out with a piece of cake, and he walked it up across the street, to the one Trump supporter.”

But Issa's staff says that's not how it happened.

“Mike obviously can’t keep his facts straight,” Calvin Moore, Issa's communications director, said in an email. “The previous picture Mike posted minutes before was the Congressman talking to his constituents.”

Indeed, Levin did post a photo of Issa speaking with constituents.

The way Moore put it, Issa “spent some time talking to a few of those gathered then headed upstairs to take a (photo) of everyone.” But Levin's tweet casts it in a different light.

Issa later tweeted a series of photos: One from the rooftop, and several (taken by Moore) of him interacting with what appears to be a lone supporter among a sea of protesters — holding a piece of cake.

There's also a photo of Issa engaged with someone who apparently wants him to “keep hands off healthcare.”

In this situation, two politicians set to face off in the 2018 election each tried to turn Tuesday into a messaging win playing out on Twitter. We're still 18 months out from Election Day 2018 — but the campaigning is clearly already underway. Democrats want to put pressure on Republicans in swing districts, and Issa's seat, in a largely liberal state, is one of the Democrats' top targets.

The Cook Political Report list's Issa's district as a “Republican toss-up,” and he won in 2016 by just a two-point margin, winning by just over 1,600 votes.

“This is a race of national significance,” Levin said, “and people are fed up with Issa's blind allegiance to Donald Trump.”

Was Issa hiding from his constituents? In this case, it might depend on whose tweets and photos you believe more.

And if anyone doubted the 2018 congressional campaign was already underway, today's messaging battle should put it to rest.

Correction: An earlier version of this post incorrectly stated the margin of Issa's 2016 election victory.