"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.
On Monday, Sessions said the Justice Department plans to withhold up to $4.1 billion from "sanctuary cities" - a blanket term for many areas that refuse immigration agents' requests to detain immigrants who entered the us illegally.
Murray said the federal government can not compel the city's police department to enforce federal immigration law.
Seattle is asking a federal court to declare that it's not breaking the law by refusing to join the Trump administration's effort to strictly enforce federal immigration laws.
The suit challenges the legality of the executive order, signed by Trump in late January, that takes aim at so-called "sanctuary" jurisdictions by threatening to withhold federal grants. If you would like to discuss another topic, look for a relevant article.More news: Rafael Nadal reaches Key Biscayne final for 5th time
According to City officials, the ambiguity of the Executive Order leaves the City unable to accurately plan its upcoming budget.
"We have to defund sanctuary cities".
"Seattle will not be bullied by this White House or this administration and today we are taking legal action against President Trump's unconstitutional order", the mayor said. Federalism experts say that case law has built up doctrines that help states maintain their resistance.
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.
"If Attorney General Sessions is so concerned about Seattle's safety, pulling law enforcement dollars from cities nationwide is the height of hypocrisy and makes us less safe", Murray said.More news: Two US courts block Trump's second travel ban
"Instead of the press conferences from the White House, instead of the tweets from the White House, we want to have a sober statement of the law that can be reassuring to the communities that this...is still a nation of laws", Holmes said.
The Justice Department on Tuesday declined to comment further.
The executive order is created to force sanctuary cities to comply with the administration's immigration policies, which Seattle's lawsuit argues would be unconstitutional under the Tenth Amendment's "anti-commandeering principle".
City leaders insisted such examples are the exception, not the rule.
Following quote is from Kyle Huelsman, Policy Manager of the Colorado Immigrant Rights Coalition (CIRC) - " By conflating ICE detainer holds and federal immigration law, Jeff Sessions is using "alternative facts" to hoodwink the American people.More news: Donald Harvey, 'Angel of Death' Serial Killer, Beaten in Prison
"Chelsea feels very strongly that treating all residents regardless of their immigration status with dignity and respect is not only the appropriate policy to have but it's also the one that secures our city the most".