Sen. Barbara Boxer, campaigning for reelection Friday on such issues as environmental protection and federal support for education, instead spent much of the day defending President Clinton and rejecting suggestions that he resign.

The California Democrat backed Clinton’s decision to order airstrikes on alleged terrorist strongholds in Sudan and Afghanistan. And she repeated her view that Sen. Dan Coats (R-Ind.) was “unpatriotic and very unwise” to suggest that the strikes were meant to divert public attention from the president’s admission that he misled the public about his relationship with Monica S. Lewinsky.

Boxer, who is related to Clinton by marriage and is one of the president’s staunchest political supporters, told gatherings in Los Angeles, Santa Barbara and Montecito that pressuring him into resigning would “tear the country apart.”

“The situation we have is this: to accept that we have a president who has lost a lot of credibility with his private life and he has to repair that with his family and the American people,” Boxer told a civic group in Montecito. “But . . . we have a president who has led us out of the deepest recession since the Great Depression, who has put education on the agenda and who has made sure we’re moving in the right direction–[including] a 30% decrease in crime.”

In Los Angeles, Boxer told reporters that she does not believe the Lewinsky matter will turn the public against Clinton. “People voted for Bill Clinton knowing he wasn’t perfect in his personal life,” she said.

Boxer, locked in a tight reelection fight with Republican Matt Fong, the state treasurer, said she looks forward to having the Clintons visit California in coming weeks to help her fund-raising effort.

Unlike some other prominent Democrats, including Sen. Dianne Feinstein (D-Calif.), Boxer has said she is satisfied with the tone and text of the speech Clinton made Monday night after he testified before a grand jury convened by special prosecutor Kenneth Starr.

“I think the president was honest, and he was angry at two people: himself and Ken Starr,” Boxer said. “He spoke what was in his heart. He took full responsibility. A lot of people say he wasn’t contrite. But the important thing is that he took full responsibility. There is no good speech for a thing like this. There is no good way to say this.”

Boxer, whose daughter is married to a brother of Hillary Rodham Clinton, said she has not spoken in recent weeks with either the president or his wife. She said Clinton’s chief of staff, Erskine Bowles, called her before the Monday speech to tell her that Clinton was going to admit to a relationship with Lewinsky.

“I told him to give my best to the [Clinton] family and tell them to have courage,” Boxer said. Still, in the minutes after the speech, Boxer issued a statement calling the relationship with Lewinsky “wrong,” a point she stressed Friday.

Boxer was present in January when Clinton made his now infamous statement that he had not had an inappropriate relationship with “that woman.”

Boxer’s temperate remarks contrast starkly with Feinstein’s raw-edged reaction to Clinton’s admission. On Monday, Feinstein issued a scathing statement that the president’s “credibility has been badly shattered.”

Professing a “deep sense of sadness,” Feinstein noted that she also “was present in the Roosevelt Room in January when the president categorically denied any sexual involvement with Monica Lewinsky. I believed him.”

Privately, Feinstein has said she felt particularly betrayed by the president because Clinton pulled her aside at that event and assured her the allegations were false. The senator was vacationing Friday and declined further comment.

Unlike Boxer, Feinstein has had touchy–at times even rocky–relations with the White House. One former staffer recalled Friday how Feinstein “made people grovel” for her vote on the president’s 1993 economic plan–the centerpiece of his first term–and opposed the North American Free Trade Agreement and Clinton’s ambitious health care reform plan.

Boxer, talking to the Channel City Club in upscale Montecito on Friday, said the Clinton administration has brought the nation “peace, prosperity and creativity unmatched in this country.” She mentioned $11 billion in federal disaster relief for California and the president’s visit to the state after devastating floods this year.

Boxer expressed confidence that Clinton and Congress can work together despite the continuing controversy over Starr’s investigation. “We have a cloud,” she said. “The question is: Do we stand under it, or do we get out and do our job?”

That isn’t good enough, said Fong spokesman Steve Schmidt. “Barbara Boxer was elected six years ago as the top Democratic attack dog attacking Republicans over inappropriate behavior. Now she’s . . . silent. . . . Her silence could impact her campaign in a major way.”

Meanwhile Friday, Boxer rejected the idea that the airstrikes would lead to an escalation in terrorism aimed at Americans abroad. “I think that’s very wrong thinking,” she said. “They were already planning other attacks on Americans. We don’t have an option. . . . We have to show terrorists that there is a price to pay.”

Boxer said she does not favor changing a U.S. policy that prohibits targeting individuals such as alleged terrorist leader Osama bin Laden for assassination. “That’s not necessary,” she said.

Times political writer Mark Z. Barabak contributed to this story.