Here's Ben Shapiro's report card on the latest GOP presidential debate:
Shapiro is usually a good read. However, I don't quite agree with his grading criteria. Mind you, he doesn't really explain what his criteria are. It's basically assumed.
There are different kinds of debate. Take a formal debate. Both sides agree on the question to be debated. The wording is important, because that determines the burden of proof.
In a debate like that, which side won or lost is based, not on which side was right or wrong, but which side did a better job of discharging their respective burden of proof. Which debater was more logical. Marshalled prima facie evidence for his position. Answered objections.
Suppose you had a debate between an atheist and a Christian. In principle, the atheist could win even though he's dead wrong, because winning and losing isn't about truth and falsehood, but how well you meet the burden of proof.
Take another kind of debate: oral arguments before the Supreme Court. The Solicitor General defends the position of the administration while a state attorney general defends state law. Now, they may privately disagree with their client. They may use arguments they don't believe. They're not representing their own position, but the client's position. They argue on behalf of the client. You grade their performance by how well or badly they field questions from the bench.
In principle, and often in practice, they may be completely insincere. They don't necessarily–or even typically–believe what they say.
Now compare that to presidential debates. That's more like a job interview. Competing applicants for the same job. What you should listen for is not so much who did the best job in the debate, but who'd do the best job as president. The criteria are very different.
In a presidential debate, unlike a formal debate (see above), having the right position on the issues is very important. And unlike lawyers who can argue both sides of a case, in a presidential debate, the candidate's sincerity is very important. Does he intend to keep his campaign promises?
It doesn't matters which contender is the best debater, but which contender would make the best candidate, and/or the best president.
For instance, Adlai Stevenson was a much better public speaker than Ike. Stevenson wrote great speeches. But I daresay Ike was a much better peacetime president than Stevenson would have been. Our enemies feared Ike. He wasn't the kind of guy they dared to put to the test.
Reagan was over the hill when he ran against Carter. More so when he ran against Mondale. On the merits, he lost his debates with Carter and Mondale. They were sharper. Better informed. Yet he had a much better vision for American domestic and foreign policy than they did.
By the same token, Reagan was bad a press conferences while Bill Clinton excelled at press conferences. Yet Reagan was a fine president while Clinton was a dreadful president.
For all his manifest limitations, Bush 43 was a better president, especially on domestic policy, then Al Gore or John Kerry would have been. That's despite the fact that Kerry, for one, bested Bush in their debates.