Colorado has become the latest state — and the first swing state — to join a group pledging to elect presidents based on who wins the national popular vote.

Eleven other states and the District of Columbia have signed onto the National Popular Vote Interstate Compact, an agreement that requires those states to select their presidential electors based on who wins the most individual votes nationwide, regardless of which candidate wins in the state.

Colorado Gov. Jared Polis signed a bill Friday bringing the state into the compact.

The compact only goes into effect once states with at least 270 electoral votes — the number needed to win a presidential election — have signed on. While the addition of Colorado brings the electoral count of states in the compact to 181, reaching the 270 point before the 2020 election appears unlikely.