For the most part, primary debates probe at differences in philosophy and strategy among copartisans, or at fundamental ideological differences between Republicans and Democrats. Or, in the case of Republican debates, a right-wing caricature of Democrats.

But candidates on the debate stage are rarely forced to grapple with the practical and pugilistic realities of general election politics—with the fact that Hillary Clinton isn’t an abstraction or a paper tiger, but a formidable candidate in her own right.

Against that backdrop, the most revealing question of the first half of the debate, addressed to Carly Fiorina, posited that Democrats will point out, accurately, that the labor market has performed better in modern times under Democratic presidents than under Republican ones, and that it performed particularly poorly under the previous Republican president.

"The Democrats will inevitably ask you and voters to compare the recent presidents' jobs performance," said moderator Gerard Baker. "In seven years under President Obama, the U.S. has added an average of 107,000 jobs per month. Under Clinton, the economy added about 240,000 per month, under George W. Bush, it was only 13,000 a month. If you win the nomination, you will probably be facing a Democrat named Clinton. How are you going to respond to the claim that Democratic presidents are better at creating jobs than Republicans?"

Fiorina, quite tellingly, had no answer.

At one point she groundlessly asserted that “problems have gotten much worse under Democrats,” basically contradicting the factually accurate premise of the question.

But Baker was right. Absent a new recession or a big economic slowdown, this is going to be not just the subtext, but the text of a Democratic candidacy.

That’s not liberal media cheerleading. That’s the expectation, I would imagine, of every intelligent operative working in Republican politics today.

“When Hillary Clinton runs, she’s going to say, ‘The Republicans gave us a crappy economy twice, and we fixed it twice. Why would you ever trust them again?’” Kevin Hassett, a Republican economist at the American Enterprise Institute, said earlier this year. “The objective for the people in the Republican Party who want to defeat her is to come up with a story about what’s not great.”

Carly Fiorina is one of the smoothest-talking Republican candidates. The fact that she didn’t have anything better than a canned answer about budgeting and tax reform to offer bodes very poorly for the GOP in 2016.