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Mayors fight Trump’s sanctuary city order 02:03

(CNN)San Francisco on Tuesday became the first city in the US to file a lawsuit over President Donald Trump’s executive order targeting sanctuary cities.

Signed January 25, the order aims to crack down on sanctuary cities, the term for jurisdictions with policies that limit cooperation between or involvement with federal immigration enforcement.

The order threatens to withhold federal funding from cities that hinder efforts to capture and deport undocumented immigrants. It contends they harm public safety.

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Cities with diverse immigrant populations have adopted various forms of sanctuary laws to counter what some considered extreme federal immigration policies, especially for minor, nonviolent crimes.

San Francisco’s lawsuit alleges the executive order is unconstitutional and exceeds the President’s power. It claims the city already complies with applicable federal law and seeks to prevent the government from cutting off funding.

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“The president’s executive order is not only unconstitutional, it’s un-American,” City Attorney Dennis Herrera said at a news conference. “This country was founded on the principle that the federal government cannot force state and local governments to do its job for it, like carrying out immigration policy. I am defending that bedrock American principle today.”

Mayors of several sanctuary cities, including San Francisco, New York and Los Angeles, have vowed to fight the order, saying it will unravel delicate relationships between immigrant communities and law enforcement and tear apart families.

Sanctuary city supporters believe that undocumented immigrants should be shielded from possible deportation when they report crimes.

One exception is Florida’s Miami-Dade County, where the Republican mayor has…