Here to speak at the Ronald Reagan Presidential Library on a sunnily perfect California day came underdog Republican presidential candidate Sen. John McCain.

Interrupted by applause 12 times in his brief remarks, McCain got what every speaker seeks: a bigger hand on the way out -- in his case a standing ovation -- than he had received on the way in.

Still, Republicans, both in their stated poll preferences and their reported campaign contributions, apparently remain committed to the son of Ronald Reagan's vice president and successor, Texas Gov. George W. Bush, whose election would, in the parlance of Reagan's film industry, be the political equivalent of a "sequel." Nobody in McCain's camp has been so cruel as to point out that only one sequel in history -- "Terminator II" starring Republican Arnold Schwarzenegger -- has ever done as well with the public as the original.

On view in this truly beautiful place is one of the most extraordinary of presidential documents: the gallant and graceful words Mr. Reagan hand-wrote in November 1994 to tell the American people that he had entered the early stages of Alzheimer's disease. "I now begin the journey that will lead me to the sunset of my life. I know that for America there will always be a bright dawn ahead." If you are unmoved after reading these words, your next of kin is legally entitled to collect on your life-insurance policy.

Historian Edmund Morris and "Dutch," his over-ballyhooed but authorized biography of Reagan, received no ovations standing or sitting from the crowd in Simi Valley. Fans of the former president resented the perceived put-down of Reagan in the book. Morris had confessed that even after 14 years, the essential Ronald Reagan somehow continues to elude him.

As one who often was publicly critical of Ronald Reagan, let me try to explain why he was so admired and liked by so many of his countrymen and even by some of us who regularly disagreed with him. Unlike nearly all of the 2000 presidential candidates, Ronald Reagan understood that the president is not the highest-ranking public employee; the president is not the manager of the federal government; nor is he the chief negotiator with Congress over details of legislation. No, the president -- as Ronald Reagan understood and regularly demonstrated -- is the leader of the nation.

In 1976 and 1980, Reagan ran for president, and he twice asked John Sears to run his campaigns. After the decisive 1980 New Hampshire primary victory, Sears and Reagan parted company at the latter's insistence. Like every campaign manager, Sears knew better than anyone -- with the possible exception of the candidate's spouse -- his boss's strengths and weaknesses.

Sears credits Reagan for forging such a strong bond with ordinary Americans. "If you really don't believe in something, people catch on. Reagan really believed."

Sears recalls the pervasive pessimism of 1980 -- the year Reagan first won the White House. "This country desperately needed optimism. He gave the country confidence. He led, and he lifted the nation."

And what about Morris's dilemma? "The rest of it," according to Sears, "is all psychobabble."

It is true. Ronald Reagan as president did repurchase our native optimism. He did remind of us what most Americans already knew: that the United States remains the greatest place on the planet.

Reagan did have real and serious flaws. My own favorite Reagan biographer, respected political writer Lou Cannon, on the eve of the Gipper's first inauguration asked "whether Reagan after being so agreeably favored by fortune can demonstrate the compassion for those who have not prospered as properly expected of an American president." Too often Reagan failed that test. Instead of comforting the afflicted or afflicting the comfortable, his presidential policies comforted the already comfortable.

Of Harry Truman it was once written that he liked being Harry Truman and that he never thought of being anybody else but Harry Truman. Of Ronald Reagan the same statement could be made. He was comfortable in his own skin. That is a pretty good threshold test for anybody who seeks to be president.