Mr. McCain instead appears to have entered Version 3 of his long and multipronged Senate career — partisan warrior and party stalwart. He takes to the Sunday TV talk shows, the Senate floor and the Capitol hallways that are filled with more reporters than mosquitoes at a garden party to press his party’s agenda on taxes, military spending and national security.

He walks largely in step with Senator Mitch McConnell of Kentucky, the Republican leader with whom he previously had an adversarial relationship that went all the way to the Supreme Court…

“I just think a lot of it has to do with the agenda,” Mr. McCain said of his re-emergence, in an impromptu interview with several reporters. “After I lost, I knew that the best way to get over it was to get active.” (Mr. McCain, who disputed some coverage of him by The New York Times during the 2008 campaign, has a policy of not speaking directly to reporters from The Times.)