Denver made its practice on immigration a policy backed by a city ordinance Monday night. The City Council unanimously passed the Public Safety Enforcement Priorities Act, sending the clearest message yet to the Trump administration that Denver won’t assist in a federal crackdown on undocumented immigrants.

The U.S. Constitution reserves immigration enforcement to federal authorities, but opponents of so-called sanctuary cities says local governments shouldn’t avow against carrying out the law.

Jon Murray of The Denver Post was the first to report Monday night that dozens of people with a stake in the immigration debate attended the public hearing that preceded the vote.

If there was any doubt the measure was a pushback against the Republican president, Councilman Paul Lopez erased it.

Lopez, who represents a heavily Hispanic district in west Denver, said local police would not be enlisted to do the dirty work of anyone, “not even a sitting U.S. president, not even a rogue agency,” Murray reported.

Denver Mayor Michael Hancock said in a statement, “Tonight, with the unanimous vote by City Council, Denver is sending a clear and resolute message to our community that we stand with the immigrant and refugee communities and are committed to remaining a city that is safe and welcoming for all. I commend and sincerely thank Council Members Paul Lopez and Robin Kniech and city staff for their leadership, as well as the community for staying engaged in this critical conversation.”

He also released the statement in Spanish.

Under the ordinance, Denver authorities won’t ask anyone about their immigration status, won’t pass along any such information they happen to receive and won’t otherwise help federal authorities with their enforcement duties.

The ordinance locks in practices the city has already endorsed and used, which is why Republicans such as state Rep. Dave Williams, R-Colorado Springs, calls Denver a sanctuary city for undocumented immigrants. Williams has tried and failed to push back with legislation during the last session, and last week he asked President Trump to get involved.

He accused Denver of being determined to allow criminals to “run loose on the streets.”

On Sunday, Hancock characterized Williams’ letter to Trump as a publicity stunt.

Denver’s ordinance, even if symbolic, was lauded by advocates on the political left as a welcome message toward Trump.

“Denver leads with values today and through their votes the City Council upheld the dignity and respect the immigrant and refugee community is entitled to under the U.S. Constitution,” Carla Castedo, Colorado state director for Mi Familia Vota, said in a statement. “I am proud of the protections guaranteed to immigrant victims and witnesses of crime, protections for our families and community members.”