Nancy Reagan has aged, but she's also grown.

The First Lady who presided over the Dazzle Years of her husband's presidency has become First Advocate for research on Alzheimer's, the disease that felled her husband.

The guardian of her husband's legacy is making history in her own right as she presses the administration of George W. Bush to open the way for research on human embryonic stem cells in hopes of finding better treatments for Alzheimer's and other diseases.

Even though the research is controversial because it involves the destruction of five-day-old human embryos. Even though the research incites the fury of the religious conservative base of the Republican Party. Even though stem cells from human embryos are unlikely to become a cure for Alzheimer's disease any time soon, if at all.

But this research holds promise for treating many other conditions from Parkinson's to spinal cord injuries. It offers hope to patients and opportunity to scientists.

Just as Nancy Reagan once urged Americans to "just say no" to drugs, she is now urging members of Congress to just say no to the government's limitations on this line of research.

And her hands still know how to work the levers of power. About a week ago, a majority of the Senate sent a letter to President Bush asking him to free up the restrictions on this new field of science -- restrictions that he imposed on the medical community nearly three years ago.

This is a long way from the attitude toward health care that was prevalent during her husband's presidency. The message from Reagan's Washington: Don't look to the government to solve your problems! In those years, another wasting disease was seizing headlines and causing havoc. AIDS was a new and misunderstood illness.

But the Reagan administration turned a deaf ear to those early cries for help. The disease -- like research on embryonic stem cells today -- was cast in moral terms. Called the 'gay plague' by some, it inflamed prejudice against homosexuality.

It took a maverick surgeon general, C. Everett Koop, to claim the moral high ground for the administration on the government's responsibility to the sick. "We are fighting a disease, not people. Those who are already afflicted are sick people and need our care," he wrote in the 1986 Surgeon General's report on AIDS. "The country must face this epidemic as a unified society."

Which is sort of what Nancy Reagan is doing today for Alzheimer's disease. She frames human embryonic stem cell research not as a moral issue but as a medical imperative. Not a partisan punching bag, but a public responsibility. To her, this is the moment to overcome divisions and face this epidemic as a unified society.

"Ronnie's long journey has finally taken him to a distant place where I can no longer reach him," she said last month at the Juvenile Diabetes Research Foundation dinner in Beverly Hills. "Because of this, I'm determined to do whatever I can to save other families from this pain. I just don't see how we can turn our backs on this [research]."

How far she has come since leaving Washington. But this is not some isolated tale of awakening. It's a common story of loss and renewal, of letting go of the past and finding new purpose. Nancy Reagan's evolution from First Lady to First Advocate is similar to those of many men and women who reinvent themselves in their later decades.

Like many couples facing retirement, the Reagans in 1989 were looking forward to their years of leisure. He was nearly 78. She was 67.

The diagnosis of Alzheimer's changed their lives. Health officials suspect that as many as 4.5 million Americans may have this devastating dementia. The cause is unknown. There is no cure. The disease usually occurs after age 60, and the risk rises with age.

Day by day, the disease invades the brain, eventually destroying all personhood. By the time of their 50th wedding anniversary in 2002, Nancy Reagan said she wasn't sure her husband knew who she was. As she said: "They were very short, the golden years."

But loss can be transforming. After a certain age, losses begin to pile up for everyone. Most are minor, but some, like the diagnosis of a major illness, are defining.

To survive, people shift their internal compasses toward a different future -- one they may never have imagined.

Nancy Reagan grieved for her loss as she cared for her sick husband. In the process, she resurrected the strengths she had built up over a lifetime. After all, here was a woman who had helped to shepherd her husband's career to the top of the political ladder.

Like many people in similar situations, she used old strengths to new purpose. While she once preferred her place behind the scenes, she has now gone public with her personal message by making speeches and writing letters to those in power. This boldness is typical of people who get to the point in their lives when they can say to themselves: If not now, when? What have I got to lose?

The psychological agenda shifts in this stage of life. Instead of getting ahead (done that), people want to make a difference. Instead of focusing on winning the next election for her husband, Nancy Reagan can turn to the broader mission of helping others. She is laying down her own legacy next to her husband's.

This kind of activism is often the hallmark of people in their Indian summer season. Their energy is fueled by a sense of urgency that is lacking in youth.

As Nancy Reagan said last month: "Science has presented us with a hope called stem cell research, which may provide our scientists with many answers that for so long have been beyond our grasp. . . . We have lost so much time already. I just really can't bear to lose any more."

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