Johnson remains popular in New Mexico and his entry into the U.S. Senate race that Democrats have been favored to win could complicate the party’s national effort to hold seats or make gains in the chamber.

Johnson’s 2016 presidential bid as a Libertarian sputtered after a live-television gaff on foreign policy. Democrats saw the presidential run, with currents of social liberalism, as a bane to their party, even as Johnson criticized Trump for his treatment of women and border-wall proposal.

Elected and re-elected governor of New Mexico as a Republican, Johnson stayed true to a small-government philosophy while vetoing more than 700 bills. His open advocacy for legalized marijuana broke mainstream 1990s political taboos and made him a national curiosity.