BEL AIR, Calif. — Former first lady Nancy Reagan endorsed John McCain for president Tuesday as the Arizona senator continued to collect backing from leading Republicans who might help him unite the party and win over critical conservative voters.

The GOP nominee-in-waiting, in the midst of a West Coast fundraising swing, stopped by the Southern California home of President Reagan's widow to accept the endorsement from the Republican matriarch he called beloved and wonderful.

"I'm very pleased and honored to have the opportunity again to be with Mrs. Reagan and to receive her endorsement for the nomination of my party and for president of the United States," McCain said in a five-minute appearance with the former first lady in the driveway of her gated home. "President Reagan and Mrs. Reagan remain an inspiration to all of us, as an example of honorable and courageous service to the nation."

In turn, she said only, "Ronnie and I always waited until everything was decided and then we endorsed. Well, obviously, this is the nominee of the party."

In a written statement issued earlier in the day, she called McCain a good friend for more than 30 years.

"My husband and I first came to know him as a returning Vietnam War POW, and were impressed by the courage he had shown through his terrible ordeal. I believe John's record and experience have prepared him well to be our next president," she said.

She and McCain met privately in the Reagan home before they emerged, arm in arm, through the front door to meet reporters.

Her eventual support was expected, and she became the latest top Republican to fall in line behind McCain. The two have long been close.

The endorsement could help him shore up the backing of conservatives who view him skeptically for his record of breaking with the party on some issues.

McCain said he hopes the endorsement brings the fractured party together and said: "This is an important, most important kind of expression of confidence in my ability to lead the party that I could have."

At the same time, a Reagan nod also could help further align him with the former president who attracted Democratic as well as Republican voters. Said McCain: "The Reagan Democrats are very important and I hope every one of them and new Democrats will be watching."

The former first lady has nurtured her husband's legacy and generally has stayed out of the political spotlight in recent years, with a few exceptions. She remained quiet during the multicandidate fight for the GOP nod but attended debates held at her husband's presidential library in Simi Valley, Calif.

In 2006, she lobbied in favor of legislation to expand federal funding of embryonic stem cell research, a position McCain shares, but President Bush vetoed the bill. President Reagan suffered from Alzheimer's disease.

She also waded into the Virginia Senate race that year when Democratic candidate James Webb, who served as Navy secretary in the Reagan administration, ran an ad featuring 1985 video footage of President Reagan praising Webb's gallantry as a Marine. Nancy Reagan's office sent Webb's campaign a letter objecting to the use of the Reagan footage.