"The Order is premised on a misreading of federal statutory law and departs dramatically from settled constitutional principles", the lawsuit, filed by Seattle Mayor Ed Murray and City Attorney Pete Holmes, states.
Leaders of sanctuary cities around the region say a new threat by Attorney General Jeff Sessions won't change their immigration policies.
Attorney General Jeff Sessions on Monday threatened to pull funding from cities that refuse to cooperate with the federal government in enforcing USA immigration law.
Seattle's lawsuit argues that Trump's order is not only unconstitutional, but also unsafe and unfair to the inhabitants of the more than 100 cities that Immigrations and Customs Enforcement recognize as having sanctuary status.
The Trump Administration's executive order, issued five days after President Donald Trump's inauguration, spelled out its hard-line stance on illegal immigration, in a policy that includes stiff penalties for cities that resist cooperating with federal authorities. If you would like to discuss another topic, look for a relevant article.
Seattle is the second sanctuary city to file a lawsuit against the executive order, after San Francisco. The order says sanctuary jurisdictions "willfully violate federal law in an attempt to shield aliens from removal from the United States".
On Jan. 25, Trump signed an executive order that would strip so-called "sanctuary cities" of certain federal grants as punishment for protecting undocumented immigrants. "We are a safer more prosperous city because of our immigrant and refugee communities and will continue standing with them".
The threats to funding come as the Trump administration unrolls a new office within the Homeland Security Department focusing on American victims of immigrant crime.
"We are not breaking any laws, and we are prioritizing safety", said Murray. "We value civil rights, we value the courts and we value the Constitution". The federal law referenced by the Attorney General (8 U.S.C. 1373) does not require any state or local jurisdiction to honor immigration detainers.
The City of Seattle has previously joined briefs against President Trump's Executive Orders on travel from specific Muslim countries and filed a set of Freedom of Information Act requests for details of the administration's definition of "sanctuary city".
Cities could miss out on grants that pay for an array of policing programs, including crime lab technology, crime prevention efforts, equipment and other services. The administration last week reported more than 200 cases of immigrants recently released from local jails before federal agents could intervene.
Critics, however, argue that these policies get in the way of enforcing federal immigration laws, tap community resources that could be used by legal citizens and protect alleged criminals.