On the third day of confirmation hearings on Capitol Hill, there was one emerging theme: Many of the nominees of President-elect Donald J. Trump have disagreements with him on policy.

There were serious questions, efforts at diversion with humor, and long-winded statements by senators. Overall, though, none of the nominees made any major mistakes, and one of them, James N. Mattis, a retired Marine Corps general, was approved as Mr. Trump’s choice for defense secretary by the Senate Armed Services Committee, 24 to 3.

Fun fact: He doesn’t care for the nickname “Mad Dog.”

Here are 10 highlights from the hearings:

■ Mr. Mattis diverged sharply from his prospective boss on Russia, calling Moscow one of the top threats to the American-led world order. “I’m all for engagement,” Mr. Mattis said, “but we also have to recognize reality in terms of what Russia is up to.”

■ Mr. Mattis also put daylight between himself and Mr. Trump on NATO and indicated strong support for the alliance’s principle of collective defense. “My view is that nations with allies thrive, and nations without allies don’t,” Mr. Mattis said.