MADISON, Wis. — Wisconsin has joined 16 other states in a joint lawsuit seeking to block President Barack Obama's executive action on immigration.

Obama's order, announced last month, spares as many as 5 million people living illegally in the United States from deportation.

Texas Gov.-elect Gregg Abbott filed a federal lawsuit Wednesday alleging Obama's unilateral action is unconstitutional. Sixteen other states, mostly in the South and the Midwest, have joined the lawsuit.

Wisconsin Gov. Scott Walker, a Republican mulling a 2016 presidential run, requested Republican Attorney General J.B. Van Hollen to join the suit. Van Hollen complied, saying it's clear that Obama exceeded his authority. Walker said in a statement the immigration system is broken but should be addressed through collaborative federal action.