US House Speaker Nancy Pelosi announced on Thursday that the House will file a lawsuit challenging President Donald Trump’s declared national emergency at the nation’s southwestern border with Mexico.

The suit is the latest in a series of efforts to stop Trump from securing funds that Congress refused to give him for his proposed wall along the border.

Pelosi said that the president violated the Appropriations Clause by “stealing from appropriated funds” without constitutional or statutory authority.

Trump’s defenders in the administration claim that his actions fall within the president’s authority to reappropriate money under urgent circumstances. There are few formal restrictions on the president’s authority to declare such emergencies, and the emergency power has been invoked by Presidents nearly 60 times since Congress passed the National Emergencies Act in 1976.

However, critics point out that this is the first time a President has invoked emergency powers as a means of securing funding for a proposal which previously failed to win legislative approval. A successful national emergency declaration would allow Trump to redirect military construction funds in order to obtain funding that was denied him by Congress.

The lawsuit has been authorized by the Bipartisan Legal Advisory Group, consisting of leaders from both parties in the House. The group met on Thursday and voted to authorize the lawsuit. The House’s lawsuit joins several others that have already been filed by other parties in response to Trump’s emergency declaration.