Obama

Substance: Quite manifestly immersed in the past, present, and future details of policy, and eager to express his views.

Grade: B+

Style: Polished, confident, focused. Fully prepared, and able to convey a real depth of knowledge on nearly every issue.

Grade: A

Offense: Though he never drew blood, he did keep McCain a bit off balance, often with clever references to McCain's recent statements.

Grade: B

Defense: Fearless, without condescension, he attempted the gracious move of agreeing with or complimenting a McCain position, occasionally to his own detriment.

Grade: A-

Overall: Went for a solid, consistent performance to introduce himself to the country... Two more performances like that and he will be very tough to beat on Election Day.

Grade: A-

McCain

Substance: His arguments were hard to follow at the beginning, but he found his voice as the debate progressed, although he never seemed fully in control of his message... If he truly knows more about the world than Obama, he didn't show it in this debate.

Grade: B-

Style: Cluttered, jumpy, and often muddled. Keenly aware of the grand, grave occasion, McCain wavered between respectful and domineering, and ended up awkward and edgy.

Grade: C-

Offense: While mocking his opponent on a few occasions, which reflected his acute disrespect for Obama, he did so in an insufficiently sharp and detailed manner -- and unevenly worked elements of his rival's record into his attacks.

Grade: C+

Defense: He managed to ignore most of Obama's jibes, but was eventually baited into giving an extended answer about his policy differences with President Bush.

Grade: B-

Overall: Failed to deliver his "country first versus Obama first" message cleanly, even when offered several opportunities.

Grade: B-

Read Mark Halperin's complete report card write-ups at TIME.com.