President Joe Biden has responded to calls to drop out of the 2024 presidential race with his own mockery of Donald Trump’s mental capacity. Speaking in Madison Wisconsin on Friday, Biden asked the crowd how their Fourth of July was. They cheered with enthusiasm. But Biden then turned to his opponent. “By the way, if you wonder whether Trump has it all together, did you ever hear how he explained the Fourth of July when he was president?” Biden asked the crowd. “No, I’m serious, this is true. His explanation of how America won the Revolutionary War, I’m not making this up. He said in his Fourt…