Words of defiance from state and Denver officials and a federal court’s ruling this week are pushing a dispute over Trump administration immigration policy closer to a confrontation before the U.S. Supreme Court.

The Justice Department sent a letter last week to Denver Mayor Michael Hancock threatening to cut off some law enforcement grants if the city continues to decline cooperation with federal immigration authorities.

The Justice Department set a deadline of Dec. 8 for the city officials to explain whether they will comply with a 1996 federal law the Trump administration says requires them to share information with the federal government on the immigration status of some individuals.

The information-sharing could be used by U.S. Immigration and Customs Enforcement to deport illegal immigrants.

So far, neither Hancock nor other Colorado politicians show any sign of backing down from their “sanctuary city” policy.

“The [Justice Department’s] letter is a constitutionally dubious attempt by the Trump administration to bully cities,” Jenna Espinoza, a spokeswoman for Denver’s mayor, said. “Denver’s immigration ordinance complies with all federal laws, including 8 U.S.C. Section 1373.”

She was referring to a federal statute that prohibits local and state governments from enacting laws or policies that limit communication with the Homeland Security Department about “information regarding the immigration or citizenship status” of individuals.

Denver and other cities argue that Tenth Amendment states’ rights give them an option to decline reporting the immigrant status of individuals as long as they are not concealing information from the federal government. They also say Trump’s immigration crackdown could make Latinos distrust the police.

Denver, like most sanctuary cities, will make public records available on request to the Homeland Security Department but does not take the initiative in collecting or reporting anyone’s immigration status.

“Denver intends to respond to the November 15, 2017, letter from the Department of Justice with our assurance that Denver’s ordinance complies with Section 1373,” Espinoza said. “Denver will not be bullied into turning its back on its immigrants and we stand ready and willing to legally challenge any actions by the Trump administration that threatens the safety and security of our residents.”

Denver’s chances of success in legal action were boosted Monday when a federal judge in San Francisco blocked an executive order from President Donald Trump to deny some federal grants to sanctuary cities.

U.S. District Judge William Orrick issued a permanent injunction after the city and county of San Francisco and Santa Clara County sued to override Trump’s order.

“The counties have demonstrated that the Executive Order has caused and will cause them constitutional injuries by violating the separation of powers doctrine and depriving them of their Tenth and Fifth Amendment rights,” Orrick wrote.

Trump promised another legal confrontation over Orrick’s ruling, making a judgment by the Supreme Court nearly certain, according to legal experts.

The warning letters the Justice Department sent to 29 cities, counties and states last week were the latest indication of Trump’s immigration crackdown. Like Denver, many of them said they would not comply.

“Jurisdictions that adopt so-called ‘sanctuary policies’ also adopt the view that the protection of criminal aliens is more important than the protection of law-abiding citizens and of the role of law,” U.S. Attorney General Jeff Sessions said in a statement explaining his letters.

He urged jurisdictions that received them to “establish sensible and effective partnerships to properly process criminal aliens.”

Federal courts rule on legal disputes between federal agencies and local governments.

So far, the Trump administration’s Justice Department has been losing consistently in immigration policy disputes with other sanctuary cities or state governments.

Last week a federal judge in Philadelphia ruled the Justice Department exceeded its authority by threatening to cut off grants to uncooperative cities from the Edward Byrne Memorial Justice Assistance Grant program.

Denver received $426,590 from the program for law enforcement activities last year, according to Justice Department records.

The court ruling in Philadelphia was preceded by a different federal judge’s ruling in Chicago in September that said the Justice Department lacks authority to make ultimatums to local jurisdictions over immigration policy.

Colorado U.S. Rep. Diana DeGette, D-Denver, joined the criticism of Trump and the Justice Department letter.

“It’s a shame the Trump administration feels the need to threaten to withhold federal funds from any jurisdiction that doesn’t agree with its draconian policies, putting millions of dollars for Colorado in question,” DeGette said. “This approach does not reflect long-held American values. It doesn’t reflect Colorado values.”

A spokesperson for Gov. John Hickenlooper shared a statement he made in March that she said remains true.

“A sanctuary city or state has no precise definition,” Hickenlooper said. “Here in Colorado we embrace our immigrant community. We remain supportive of efforts to secure borders, which includes deporting undocumented immigrants who have committed serious crimes. This conversation is another example of the need for Congress to step up and provide comprehensive immigration reform.”