EntertainmentCan it really be 40 years ago this weekend that the bungled “third-rate burglary” at the Watergate Hotel marked the beginning of the end for a President of the United States? Richard Nixon was already a polarizing figure when his efforts to cover up the White House-Watergate connection were first hatched. But his astonishing fall from power is the stuff of high drama—and it’s not surprising that to this day Hollywood’s most gifted actors seem compelled to take a shot …