California and at least a dozen other states will be joining a lawsuit to challenge President Donald Trump’s national emergency declaration, California Attorney General Xavier Becerra said Monday. “The president admitted that there’s not a basis for the declaration, he admitted there’s no crisis at the border, he’s now trying to rob funds that were allocated by Congress legally to the various states and people of our states,” Becerra told MSNBC. “The separation of powers is being violated, we’re going to go out there and make sure that Donald Trump cannot steal money from the states and people who need them, since we paid the taxpayer dollars to Washington, D.C. to get those services.”

Speaking on CNN, Becerra said the lawsuit is imminent. “We should be filing sometime today,” Becerra said. “We’re going to try to halt the President from violating the Constitution, the separation of powers, from stealing money from Americans and states that has been allocated by Congress, lawfully.”

This marks the latest effort to challenge Trump’s emergency declaration in the courts. Earlier, three environmental and advocacy groups joined a lawsuit against the emergency declaration. The Center for Biological Diversity, Defenders of Wildlife and Animal Legal Defense Fund filed a lawsuit over the weekend arguing that the White House doesn’t have the authority to use emergency funds to build a wall along the Mexico border. “The only emergency here is Trump’s assault on the Constitution,” said Brian Segee, a senior attorney at the Center for Biological Diversity, in a statement. “Separation of powers is at the heart of our democracy and the power of the purse is a critical check on the president. Trump’s authoritarian attempt to build his destructive border wall is a flagrant abuse of that constitutional structure. If he gets his way, it’ll be a disaster for communities and wildlife along the border, including some of our country’s most endangered species.” This came after the advocacy group Public Citizen also filed a lawsuit on behalf of three Texas landowners and an environmental group. The American Civil Liberties Union also said it was preparing a lawsuit claiming that Trump doesn’t have the authority to redirect taxpayer money to build a wall.

All the lawsuits shouldn’t come as a surprise to the White House. In fact, Trump said he fully expected to be sued when he announced the emergency declaration Friday, but he was confident his administration would eventually come out on top of any legal challenge. “And I’ll sign the final papers as soon as I get into the Oval Office. And we will have a national emergency, and then we will then be sued, and they will sue us in the Ninth Circuit, even though it shouldn’t be there,” Trump said. “And we will possibly get a bad ruling, and then we’ll get another bad ruling. And then we’ll end up in the Supreme Court, and hopefully we’ll get a fair shake. And we’ll win in the Supreme Court, just like the ban.”

Challenge to the emergency declaration could also come from Congress, where lawmakers could put forth a joint resolution to terminate it. But White House adviser Stephen Miller hinted Trump wouldn’t hesitate to cast the first veto of his presidency if lawmakers tried to undo his emergency declaration. “Obviously the president is going to protect his national emergency declaration,” Miller said on Fox News Sunday.