Super Tuesday was a pretty good night for Donald Trump as he took one step toward the once-implausible goal of becoming the Republican presidential nominee.

But anyone watching the proceedings at the Mar-a-Lago Club knows the real star of last night's Trump presser was in the supporting role: Chris Christie, gazing uncomfortably as he stood behind the man he endorsed, transfixed Twitter.

Where Twitter led, the media followed. Sure, some of the coverage of the Christie stare was blatantly tongue-in-cheek. And in a campaign where candidates have vilified the media, a little bit of schadenfreude is to be expected.

But many thought that last night on stage they saw a man who was conflicted about his endorsement. Was that the actual story?

Probably not, says Matt Katz of WNYC, who was part of the team that won a Peabody award for their reporting of the Bridgegate scandal.

Katz has covered Christie for the past five years and has since become the country's unofficial Christie-watcher-in-chief.

As he was tweeting during the conference "Christie always has dour expressionless mug when standing behind someone at podium... Except he's one usually being introduced."

Reached by phone, Katz said that he's seen Christie introduced "many, many times," and every time he is behind a podium waiting for the speaker to finish his "eyes are darting, his look is dour and expressionless and his hands hang loosely off his frame."

A good part of why this look conquered the Twittersphere, Katz thinks, was the camera angle. At the beginning of the conference the camera showed one of Trump's sons on stage. Christie (min 2:51) is seen motioning to him to come stand next to him but he declines.

The camera zooms in and the contrast between Trump and Christie's face becomes decidedly comical.

Even if the stare itself wasn't the live rendition of a politician grappling with the moral consequences of his choices, Katz says it is emblematic of Christie's capacity to inject himself into a news cycle. For good or for ill, Christie — not Trump or Clinton — was the top trending topic on Twitter last night.

Katz also thinks Christie's overall deferential tone is indicative that he is willing to entertain a job offer from a future President Trump.

Christie's return on the campaign trail means Katz, who also has a book out on Christie, has become a lot busier again, too.

In a situation familiar to other reporters specializing on a topic, his agenda closely tracks Christie's presence in the news (just check out the ups and downs of his Twitter engagement).

As long as Christie continues being a key surrogate and supporter for Trump, what should reporters covering the New Jersey governor on the campaign trail be on the lookout for?

Katz says Christie hasn't taken questions about the campaign from the New Jersey press since endorsing Trump; he hopes that if national reporters get a chance to talk to him they will concentrate on the contrast between Christie's and Trump's positions on minorities.

"A fascinating part of his personal political history is his longstanding effort to reach out to minority communities," Katz says. As a student body president in the '80s, Christie launched a committee on diversity; when his appointment of a Muslim judge led people to wonder whether he would implement sharia he said he was "tired of dealing with the crazies." In his 2013 re-election, he took home 51 percent of the Hispanic vote.

But is it worth it for a newsroom and a reporter to tie so much reporting to a big state-level player?

Katz says it is a gamble. Christie is a "surprising and confounding politician," who makes for interesting subject matter.

That said, when Katz signed on to a biography deal, both he and his publisher expected Christie to stay in the presidential race a little past New Hampshire. If anyone similarly followed one-time rising star Bobby Jindal expecting a successful presidential run, they are likely even more disappointed.

Aspiring reporters eyeing similar beats should know they will be able to provide "useful historical perspective" if their politician becomes a big national player, Katz says. He is also aware, however, that once Christie hit the national campaign trail he wasn't as "sourced up" about other key players outside the state as national political reporters.

How long will Katz, who has also written about Afghanistan, continue making the New Jersey governor his de facto beat?

"I honestly don't know."