The second and third possibilities – a candidate is “discovered” or “scrutinized” –  are much more interesting. The terminology here comes from “The Gamble” – an excellent book on the 2012 election by George Washington University Professor John Sides and UCLA Professor Lynn Vavreck. Sides and Vavreck studied the 2012 Republican primary and found that many of the candidates who enjoyed a brief moment atop the polls did so because of a media “discovery, scrutiny and decline” pattern. In the discovery phase, a relatively unknown candidate does something that attracts the attention of journalists (e.g. Herman Cain winning the Florida Straw Poll). These journalists become fascinated with that candidate, write a ream of stories about him or her (often neutral-to-positive in tone) and as a result that candidate rises in the polls. These same journalists then write positive stories about that candidate’s rise, and the candidate rockets to an even higher position. Thursday’s debate could focus the media’s attention on a new candidate. For example, if Ohio Gov. John Kasich has a breakout performance in the main debate or if Carly Fiorina dominates the second-tier candidate debate earlier in the evening, the media could “discover” them and cause a subsequent rise in the polls. Of course, this might not happen, but a good debate performance provides a plausible springboard for a media-fueled poll bounce.

It’s also possible that this debate kicks off the “scrutiny” phase of Trump’s candidacy. According to Sides and Vavreck, scrutiny happens after the candidate has had some time atop the polls and journalists decide to really dig into their public record and personal history. Right now Trump is firmly in the discovery phase of his candidacy. The media are still treating him as more of a celebrity than a candidate, so his policy positions and his past are getting less attention than his performance in the latest poll or his most recent bombastic statement. If the media and party establishment begin to scrutinize Trump in the way they would any other politician, it may lead to bad press and a related drop in his poll numbers – the beginning of the “decline” in Sides and Vavreck’s process.

That’s not to say that Trump will definitely be scrutinized after the debate. And the scrutiny may have a muted or delayed effect – part of Trump’s appeal is his aggression towards the mainstream media and political establishment. But it is possible that the debate marks a turning point in how Trump is viewed – and if that’s the case, then it has potentially huge consequences.