President Donald Trump is suing the Jan. 6 select committee and the National Archives to block the release of his White House’s records related to the Capitol attack.

The former president’s lawyers filed the suit in D.C. district court on Monday. It names the Jan. 6 panel’s chair, Rep. Bennie Thompson (D-Miss.), and the national archivist, David Ferriero, along with the committee and the archives. And it calls the Jan. 6 probe “a vexatious, illegal fishing expedition.”

In the lawsuit, Trump’s lawyers ask a federal judge to declare the entire request from the select committee to be invalid and to block the National Archives from turning over any materials to Congress in response to the request. They also specifically ask the court to block the Archives from turning over any documents that Trump says are covered by executive privilege.

And Trump’s team also asks for the court to have the Archives first identify all the documents from Trump’s White House that could be responsive to the request, and then let Trump’s lawyers review them in their entirety before sharing them with Congress. That process could take years.

The lawsuit kicks off a complex, high-stakes legal fight over congressional investigations and executive privilege. In the Nixon era, the Supreme Court acknowledged that former presidents may have an interest in shielding documents from public view. But this is the first public legal dispute between a current president and his predecessor over whether to assert executive privilege.

This new lawsuit was several months in the making. The Jan. 6 select committee asked the National Archives in late August for voluminous records related to Trump administration communications on the day of the attack. It also asked for documents going back to April 1, 2020, related to Trump’s plans for the presidential campaign, including records concerning polling and any documents given to Trump predicting he might lose his re-election bid.

Following that request and according to standard practice, the head of the archives then sent hundreds of pages of those records to Trump and his lawyers to review. That was just the first batch of material; the archivist is still reviewing reams of documents for records that may also be responsive to the request, and is sending those records to Trump for review on a rolling basis.

Trump and his team determined that at least three dozen of the records from that first batchwere covered by executive privilege — meaning that, in their view, Trump had a right to keep them secret. Trump sent a letter to the archivist on Oct. 8, which POLITICO reviewed, stating his position and telling the archivist to withhold the documents.

But the Biden White House has taken a different position on whether or not those records can be released. Biden’s White House counsel, Dana Remus, told the archivist later on Oct. 8 that the president wanted the documents provided to the Hill.