After Ron Reagan, Ronald Reagan’s younger son, revealed that his late father’s Alzheimer’s disease began while he was in the White House, the former president’s sons have clashed over the former president’s political legacy.

In a new biography, his son claims that former President Ronald Reagan, who was diagnosed with Alzheimer’s disease five years after leaving office, displayed indications of the disease while still in the White House.

According to extracts from his book “My Father at 100,” Reagan’s son believes his father would have left office if the sickness had been diagnosed at the time.

The squabble brings up a long-discussed topic: when did the 40th president’s mental health begin to deteriorate as a result of the disease? In 1994, five years after leaving office, he was formally diagnosed with Alzheimer’s disease. Reagan died at the age of 93 ten years later.

Reagan claims that three years into his father’s first term, he sensed trouble.

After watching his father debate Democratic presidential contender Walter Mondale in 1984, Ron Reagan said, “I began to experience the nausea of a bad dream coming true.”

“My heart sank as he floundered his way through his responses, fumbling with his notes, uncharacteristically lost for words. He looked tired and bewildered.

“Some voters were beginning to imagine grandpa — who can never find his reading glasses — in charge of a bristling nuclear arsenal, and it was making them nervous,” said Ron Reagan, according to a published excerpt of his book.

“I’ve seen no evidence that my father (or anyone else) was aware of his medical condition while he was in office,” Reagan wrote.

He suspects his father had Alzheimer’s in 1986, when he was flying over familiar canyons north of Los Angeles and couldn’t recall their names.

Reagan, who was 73 years old at the time, comfortably won reelection, defeating Mondale in the Electoral College by capturing 49 states.

“Today we are aware that the physiological and neurological changes associated with Alzheimer’s can be in evidence years, even decades, before identifiable symptoms arise,” he wrote. “The question, then, of whether my father suffered from the beginning stages of Alzheimer’s while in office more or less answers itself.”

Michael Reagan, who was adopted by the president and his first wife, Jane Wyman, speaks out against this. His book, The New Reagan Revolution, is a call for a return to his father’s political ideas of low taxes and limited government as a means of restoring America’s greatness.

He used Twitter to lash out at his brother. One tweet stated, “What a way for Ron to say Happy 100th Birthday Dad.

“Ron, my brother, was an embarrassment to his father when he was alive and today he became an embarrassment to his mother,” said another.

Reagan, a former Hollywood actor and governor of California, was not diagnosed with Alzheimer’s disease during his administration, according to White House physicians.

Reagan’s son, on the other hand, believes his father was sick.

Ron Reagan’s book will be released on Tuesday, just in time for his father’s 100th birthday on February 6.

The story of the Reagan brothers is a reflection of the polarization that has gripped the United States in recent decades. They’ve taken up opposing positions in the political ring.

Ron Reagan displayed an independent spirit from an early age, proclaiming himself an atheist at the age of twelve. He went on to become a presenter of liberal and progressive viewpoints on left-wing outlets including MSNBC and the now-defunct Air America radio network.