MSNBC’s Joe Scarborough ridiculed Donald Trump’s ongoing obsession with Barack Obama. The quadruple-indicted former president seems to think he’s running against his predecessor, who hasn’t been in office since early 2017, and the “Morning Joe” host said Trump has never gotten over Obama mocking him at the 2011 White House Correspondents’ Dinner. “I’m dead serious, you followed this guy a very long time,” Scarborough said. “There is the confusion between Nikki Haley and Nancy Pelosi, the continued confusion between Barack Obama and Joe Biden. That has a deep background, going all the way back …