That was Reagan talking into what he thought was a muted mic. That it was a joke is obvious. You know darn well Reagan wouldn't have made that kind of joke if he had known the mic was hot. Trump, on the other hand, tells the kinds of "joke" he secretly wish were true, and not jokes, but if he gets a bad reaction, he can backpedal and claim they were a joke. A few times he made that claim, upon reviewing the video, it's not obvious he was joking at all.
But, apparently Trump can't even grasp what a joke is or isn't, so how can he claim he was joking? Just like the time he sued Bill Maher for failing to live up to his "contract" where Maher told Trump he would pay him $5 million if Trump could prove he wasnt the spawn of an orangutan. Predictably, Maher refused to pay. When asked about why he sued, and why the judge threw out the suit, Trump said "I didn't realize Maher was joking", I guess it was the elusive clues about "orangutan" and Maher beingi a well-known comedian and all.
Let's face it, Trump is a moron, the evidence is clear.
Intelligent people can see right through Trump, especially when it comes to this kind of thing.