The Governor of Wisconsin is the head of the executive branch of Wisconsin's state government and the commander-in-chief of the state's army and air forces. The governor has a duty to enforce state laws, and the power to either approve or veto bills passed by the Wisconsin Legislature, to convene the legislature, and to grant pardons, except in cases of treason and impeachment. The position was first filled by Nelson Dewey on June 7, 1848, the year Wisconsin became a state. Prior to statehood, there were four governors of Wisconsin Territory.