Washington State Attorney General Bob Ferguson speaks at a news conference about the state's response to President Trump's revised travel ban Thursday, March 9, 2017, in Seattle.
FILE - Washington state Attorney General Bob Ferguson speaks at a news conference about the state's response to President Donald Trump's revised travel ban, March 9, 2017, in Seattle. Ferguson on Sept. 19, 2019, sued Trump over border wall funding.

Washington state's attorney general is suing U.S. President Donald Trump to try to stop him from diverting $89 million from a military project to help fund the border wall with Mexico.

State Attorney General Bob Ferguson filed his lawsuit Thursday in a federal court in his state.

"Our nation's founders enshrined our system of checks and balances in our Constitution. President Trump's action threatens to undermine that system. We will not allow that to happen," Ferguson said.

He asserted that Trump's plan to divert military funds to the border wall was unconstitutional because Congress didn't authorize the money for the wall.

Ferguson said that no matter how anyone feels about immigration or Trump politically, the president had committed an "egregious abuse of power."

Democratic Governor Jay Inslee added that "the president promised that Mexico would pay for his vanity border project, but instead it is U.S. military members, their families and their communities who are paying for it."

Submarine base

The $3.6 billion for already approved military projects that Trump wants to use for the wall include $89 million for upgrades to the Bangor submarine base on Washington state's Kitsap Peninsula.

The base is home to the U.S. Pacific fleet of Trident ballistic missile submarines.

The Pentagon says building a new pier and maintenance facilities at the base is important to sailors and their families. It says the current facility is no longer adequate, and that when submarines cannot dock because of a lack of space, sailors are forced to remain at sea and away from their families.

It also says current fueling facilities at the base are expensive to operate and a danger to the environment.

There has been no response so far from the White House to the Washington state lawsuit. 

FILE - Government contractors erect a section of border wall along the Colorado River, Sept. 10, 2019, in Yuma, Ariz.

Trump declared an emergency at the U.S. southern border earlier this year because of the thousands of Central American migrants trying to make their way into the United States.

Under Trump's plans, 127 military construction projects in 23 states and overseas for which Congress had already approved funding will either be canceled or postponed.

Attorneys general in 20 other states have also filed legal challenges.