From 1973 until 1974, Haig served as Richard Nixon's White House Chief of Staff and from 1974 to 1979, Haig served as the Supreme Allied Commander of NATO.
After an unsuccessful run for the Republican Party nomination for President in 1980, he acted as Ronald Reagan's Secretary of State until 1982. He received criticism in 1981, after the assassination attempt on Reagan, for asserting before reporters that "I'm in control here" as a result of Reagan's hospitalization, although in fact he was not in charge under the rules of constitutional succession, as laid out by the Twenty-fifth Amendment to the Constitution and by U.S. law.