Next month it will be 10 years since Ronald Reagan died at age 93. Next fall it will be 20 years since he withdrew from public view by releasing his handwritten letter announcing he had been diagnosed with Alzheimer’s disease, and 30 years since he was re-elected with 59 percent of the vote, carrying 49 of 50 states — a political feat no one has come close to since. And it will be 50 years since his late October telecast for Barry Goldwater made him a national political figure.