U.S. Sen. John McCain’s presidential exploratory committee announced Tuesday that former Maine Gov. John R. McKernan Jr. (photo) will support the Arizona senator should he decide to seek the presidency. “John McCain has a special and invaluable ability to rally popular support around the principled position,” said McKernan. “As a Republican, I appreciate that trait, but as an American concerned about the future generations of this country, I believe we need it.” McKernan served as Maine’s chief executive from 1987 to 1995. Before that he was a two-term U.S. representative. McKernan is currently the executive chairman and chairman of the board of the Education Management Corp. He is married to Maine’s senior U.S. senator, Olympia Snowe.