Sixteen states, including California, New York, and Michigan, are suing over Trump’s decision to declare a national emergency to obtain funding for a border wall.

The suit against the Trump administration is the latest one the White House faces over the president’s announcement. The ACLU as well as the nonpartisan nonprofit Protect Democracy have also said they’ll pursue lawsuits against the Trump administration.

The states’ lawsuit, much like the others, argues that the Trump administration is bypassing Congress’s constitutional authority over federal funding and hurting states in the process.

“If the President is essentially stealing money that’s been allocated to go to the various states for various purposes but no longer will, we’re being harmed, our people are being harmed,” California Attorney General Xavier Becerra told CNN on Monday.

Both congressional Democrats and Republicans have expressed concerns that Trump’s decision to use a national emergency to tap into different pots of funding, including money authorized for counternarcotics programs and military construction, marks an unprecedented expansion of executive power.

What’s unique about Trump’s declaration is the aim to obtain funds for a wall after Congress explicitly declined to fund it. Since Congress is given the ability to allocate federal funds by the Constitution, many lawmakers have argued Trump’s emergency declaration is a unilateral means of getting around the legislature.

“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,” Becerra emphasized in an MSNBC interview.

There will be lots of challenges to Trump’s declaration

It’s unclear whether the states or activist groups have a firm enough legal footing to win their respective challenges against Trump. But it’s certain that there will be many lawsuits filed over the emergency declaration.

Although Trump has by his own admission suggested that he didn’t “need to” declare this emergency, the National Emergencies Act itself gives presidents a wide berth to take advantage of it, making it tougher to field an effective challenge.

Additionally, congressional Democrats are weighing a couple different ways to push back on the emergency declaration, including the use of a resolution that would terminate it.

As established by the National Emergencies Act, Congress has the ability to terminate the declaration if both chambers decide to do so via a simple majority. Because Trump is expected to veto a resolution like this if it passes, Democrats would need a number of Republicans to join them to make up a two-thirds veto-proof majority in the House and the Senate. Given Republicans’ aversion to explicitly confronting Trump, it’s unlikely they’ll be able to reach that threshold.

Landowners along the southern border who could see their land seized for wall construction via “eminent domain,” would also likely have standing to sue to prevent this seizure.

This is far from the first time various states have tried to take on Trump.

As the Los Angeles Times reports, California alone has already sued the Trump administration at least 38 times including over the constitutionality of the travel ban.