Gov. Jared Polis on Friday quietly signed a bill that pledges Colorado’s Electoral College votes to the presidential candidate who wins the national popular vote.

The National Popular Vote Act makes Colorado part of a multi-state compact — but it only takes effect if and when enough states join to control 270 electoral votes.

The bill had no Republican support in either chamber, and opponents announced plans Friday to ask voters to overturn the law.

“With the overwhelming support that (Monument Mayor Don) Wilson and I have received from people statewide, we are ready to start circulating the petitions so we can get this on the 2020 ballot and let the People of Colorado decide how their electoral college votes should be cast,” Mesa County Commissioner Rose Pugliese said in a statement.

The Secretary of State’s Office said it would complete the necessary paperwork Friday allowing signature-gathering to begin. They’ll need 124,632 valid signatures by Aug. 1 to put the question on the 2020 ballot.

The bill’s sponsors — state Sen. Mike Foote and Reps. Jeni Arndt and Emily Sirota, all Democrats — released a joint statement saying using the national popular vote will give each person in Colorado and across the nation an equal vote.

“Equal representation is not a red or blue issue – it is a way to ensure every American and every Coloradan has an equal say about who leads our country. We are proud that Colorado has joined the compact,” the statement said.