Sen. John McCain (search), R-Ariz., said Thursday he did not believe Democratic candidate John Kerry (search), a friend and Senate colleague, was weak on defense or would compromise national security if elected president.

"This kind of rhetoric, I think, is not helpful in educating and helping the American people make a choice," McCain said on "The Early Show" on CBS. "You know, it's the most bitter and partisan campaign that I've ever observed. I think it's because both parties are going to their bases rather than going to the middle. I regret it."

Republicans, including President Bush and Vice President Dick Cheney (search), have sharply criticized Kerry on a range of defense and security issues, including not supporting the war in Iraq, voting against a measure to provide the war effort $87 billion, and voting against weapons systems critical to waging war.

"The senator from Massachusetts has given us ample doubts about his judgment and the attitude he brings to bear on vital issues of national security," Cheney said in a speech Wednesday.

Asked on NBC's "Today" if he thought Kerry was weak on defense, McCain said: "No, I do not believe that he is, quote, weak on defense. He's responsible for his voting record, as we are all responsible for our records, and he'll have to explain it. But, no, I do not believe that he is necessarily weak on defense. I don't agree with him on some issues, clearly. But I decry this negativism that's going on on both sides. The American people don't need it."

When asked on "The Early Show" if Kerry's election would compromise national security, McCain responded: "I don't think that — I think that John Kerry is a good and decent man. I think he has served his country."

McCain, Bush's rival for the Republican nomination in 2000, said he believes Bush has led the nation with clarity since the terrorist attacks of Sept. 11, 2001, and that he supports Bush's re-election. "But I would certainly hope that we could raise the level of this debate. Otherwise, we're going to have very low voter turnouts in November," he told CBS.

McCain and Kerry, both decorated Navy veterans of the Vietnam War, have worked together on veterans issues in the Senate. Although McCain said last week he would consider an offer from Kerry to be his running mate, McCain's office later issued a statement saying he would not run with Kerry.

"I don't want to be vice president of the United States. I do not want to leave the Republican Party. I would not be vice president of the United States on either ticket," McCain told CBS on Thursday.