President Trump’s personal attorneys filed a lawsuit Thursday seeking to block a Manhattan prosecutor’s subpoena of his accounting firm.

The lawsuit, filed in a federal court in New York, is a broad attack on the efforts by the local prosecutor to investigate Trump while he is in the White House. Trump’s attorneys are positioning the subpoena dispute as a test case that could secure a ruling declaring that all criminal investigations into a sitting president are unconstitutional.

“In response to the subpoenas issued by the New York County District Attorney, we have filed a lawsuit this morning in Federal Court on behalf of the President in order to address the significant constitutional issues at stake in this case,” Trump attorney Jay Sekulow said in a statement.

A copy of the lawsuit is not yet available on the federal judiciary’s website, but was obtained by CNN.

It was reported earlier this week that the office of Cy Vance, the Manhattan district attorney, had subpoenaed Trump financial records — including eight years of his tax returns — from his accounting firm, Mazars.

It appears that the subpoena, issued late last month, was part of an investigation into the hush money payments to women claiming sexual encounters with Trump and whether the reimbursements for those payments were falsely accounted for by Trump’s business as a legal expense.

Trump’s personal attorneys had previously brought lawsuits seeking to block a U.S. House subpoena of Mazars and Trump’s banks for his financial records.

While those cases focused on the legality of congressional investigations into Trump, the latest lawsuit is aimed at criminal investigations conducted by state and local prosecutors. The lawsuit was filed against both Mazars and Vance.

“Because the Mazars subpoena attempts to criminally investigate a sitting President, it is unconstitutional,” the new complaint said. Trump’s attorneys also filed a request for temporary restraining order that would immediately block the subpoena, according to court docs published by Courthouse News.

With the longstanding Justice Department opinion that federal prosecutors are unable to bring criminal cases against a sitting president — an opinion that constrained special counsel Robert Mueller’s ability to say whether Trump illegally obstructed justice in his probe — more attention has been paid to the ability to state and local prosecutors to hold Trump to account for potentially criminal acts.

Thursday’s lawsuit acknowledged that “no court has had to squarely consider the question” of whether criminal investigations into a President were unconstitutional.

It instead leaned on the assessments of legal commentators who have questioned the constitutionality of a criminal prosecution of a sitting president.

The complaint pointed specifically to the role of impeachment that is outlined in the Constitution.

For a court to permit criminal investigations into a sitting president “would allow a single prosecutor to circumvent the Constitution’s specific rules for impeachment,” Trump’s personal attorneys said.

“[T]he Constitution prohibits States from subjecting the President to criminal process while he is in office,” the lawsuit said.

Additionally, Trump’s lawyers echoed arguments they’ve made in other court cases alleging that New York prosecutors are being motivated by a partisan desire to harass and embarrass the president. They also compared the district attorney’s subpoena to the House’s to suggest that Vance had cut-and-pasted the House subpoena.

According to the new lawsuit, Trump’s attorneys attempted to negotiate with Vance and he refused to narrow the subpoena.

Read the lawsuit via CNN here.