If you’d spent the past eight months hiking the Appalachian Trail, and Thursday night’s GOP presidential debate was the first whiff you’d gotten of the candidates in action, you’d be more than a little surprised to see Donald Trump at center stage, where the polling front-runner normally stands.  And maybe you’d be wondering where Wisconsin Gov. Scott Walker went.  But by the end of the nearly two-and-a-half-hour debate, you’d have a reasonably good understanding of the dynamics of the Republican race. 

You’d see, in Trump, a lot of political “street smarts.”  You’d see a willingness to draw from a populist grab bag of topics (tariffs on China; a ban on Muslims entering the United States) that candidates from both parties usually avoid.  You’d also see plenty of self-indulgence on process topics such as Ted Cruz’s “natural born” citizenship, and a willingness to pontificate on topics he clearly knows nothing about.  You’d notice that several of Trump’s opponents seemed too intimidated to attack him.  You’d see Trump wobble — sometimes badly, such as in his initial exchange with Cruz — and then recover, almost miraculously. 

You’d see, in Cruz, a smart tactician who serves up plenty of red meat, and who (perhaps more effectively than any other candidate) plays to both the debate hall and the home viewing audience.  You’d also see a candidate who doesn’t invite sympathy and can overextend himself, sometimes tempting an effective counterattack, like the one Trump got in about “New York values” and 9/11. 

You’d see, in Marco Rubio, the ultimate glass-half-full, glass-half-empty candidate.  Just when you thought Rubio was finally going to have his breakthrough moment (his opening answer was effective and flashed anger that Rubio has sometimes been lacking), he’d disappear for long stretches of time, with competent but canned-sounding answers that failed to raise him above the fray.  Then just about when you were ready to count Rubio out, he’d surprise you with an effective strike, like the one he carried out against Cruz on immigration and other topics toward the end of the debate. 

You’d see, in Chris Christie, a candidate who seemed to be on the fringe between top tier and second tier.  You’d notice that he was using his personality to mostly good effect (this wouldn’t have been true if you’d watched some of Christie’s earlier debates).  You’d see that, like Cruz, he was a good tactician.  But you’d also wonder if his blows were landing as effectively with the home audience of conservative Republicans as they were on stage. 

You’d see Jeb Bush, and wonder why a candidate who was once one of the front-runners was standing over yonder in 4-percenter territory.  Then you’d witness Bush’s seeming inability to read the moment.  He’d invite a fight with Trump over Trump’s proposed Muslim ban — a slightly risky tactic given where Republican voters poll on the issue, but perhaps worthwhile if Bush wants to appear dignified and presidential — only to be oddly ineffective in delivering his punch, bogging himself down in process instead of principles. 

You’d see John Kasich and wonder if his goal was to win New Hampshire, or maybe just to get liberal pundits to say nice things about him on Twitter. 

You’d see Ben Carson and wonder if he had a pulse. 

All right, you get the point.  But I noticed that in the grades we collected from the FiveThirtyEight staff tonight, there was a strong correlation between how much success we thought the candidates had in the debate Thursday night and how well they’re doing in the nomination race overall. 

CANDIDATE AVERAGE GRADE HIGH GRADE LOW GRADE Ted Cruz B+ A C+ Donald Trump B A- C- Chris Christie B B+ C+ Marco Rubio B- B+ C Jeb Bush C+ B D John Kasich C B D Ben Carson D+ C F

Not a perfect correlation — we had Cruz having the slightly better debate than Trump, when Trump remains ahead of him in polls.  But the debate was still the closest thing we’ve seen to the GOP campaign in microcosm. 

Check out our live coverage of the Democratic debate.