OAKLAND (CBS SF) – A federal judge will hear arguments in Oakland Friday on requests by 20 states and the Sierra Club for a preliminary injunction blocking President Donald Trump’s national emergency plan to divert federal funding to border wall construction.

Trump announced the plan to divert $6.7 billion from several government agencies in February after declaring a national emergency.

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U.S. District Judge Haywood Gilliam will hear claims in two lawsuits filed by 20 states led by California and by the Sierra Club and a coalition of southern border groups.

The states and groups contend Trump’s plan violates Congress’ constitutional power to decide on budget appropriations.

The government’s actions amount to “disregard of the will of Congress and violation of fundamental separation of powers principles enshrined in the United States Constitution,” California Attorney General Xavier Becerra wrote in a brief submitted to Gilliam.

U.S. Department of Justice lawyers say the funding plan is within the president’s powers and does not even depend on the declaration of a national emergency.

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They wrote, “The statutes the government has relied on provide longstanding and express authority to use specific sources of appropriated funds for law-enforcement or drug-interdiction purposes.”

The two lawsuits also argue the wall construction will harm the environment and must therefore be subject to a study and public comment under the requirements of the National Environmental Policy Act.

Trump declared the national emergency, citing a security and humanitarian crisis at the southern border, after Congress refused to appropriate the $5.7 billion he requested for wall funding, and instead granted $1.375 billion.

Several other challenges to the funding plan are pending in federal court in Washington, D.C.

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