After Watergate, but before the impeachment of President Bill Clinton, there was Gary Hart. By every measure, the charismatic Colorado senator was the front runner for the 1988 Democratic presidential nomination, with widespread support from young voters, a command of policy issues, and a knack for connecting with audiences. But the events of a single week in May 1987 proved a new era was dawning in politics. “I think the reason people get into politics is because there’s this incredible chess game going on,” said Hugh Jackman, who plays Hart in the new film “The Front Runner,” opening Nov.