President Donald Trump’s personal lawyers asked the Supreme Court on Friday to step into an escalating clash between the legislative and the executive branches and block a House subpoena for Trump’s personal financial documents.

The dispute goes to the heart of Congress’ power to investigate and further its legislative function amid broad claims from Trump that the congressional committee has exceeded its authority.

In an emergency petition, the lawyers are asking the Supreme Court to put a federal appeals court opinion on hold while they prepare to ask the high court to add the case to this term’s docket.

“For the first time in our nation’s history, Congress has subpoenaed the personal records of a sitting President from before he was in office,” Jay Sekulow, the President’s personal lawyer, said in a statement. “In light of the significant constitutional issues involved in this case, we are hopeful that the stay will be granted pending the timely filing of a Petition for Certiorari on behalf of the President.”

The request is directed to Chief Justice John Roberts, who has jurisdiction over the US Court of Appeals for the District of Columbia Circuit. Roberts will likely refer the filing to his colleagues for their review.

This is the second Trump tax-related case to go to the Supreme Court in recent days.

The Supreme Court could find itself at the center of a dispute that is tangentially connected to an array of other lawsuits percolating in the lower courts. Unlike some of those cases, however, Friday’s dispute, which was launched well before the current impeachment proceedings, touches specifically on the House’s subpoena powers.

The case arises from a subpoena issued by the House Committee on Oversight and Reform last April to Trump’s long-time accounting firm for financial documents concerning the President and his companies for the years both before and during his presidency. The committee’s investigation entails, among other subjects, whether the President had undisclosed conflicts of interest.

In court papers filed Friday, Sekulow argued that allowing the subpoena to go forward would mean Congress is free to investigate every detail of a President’s personal life.

“Given the temptation to dig up dirt on political rivals, intrusive subpoenas into personal lives of Presidents will become our new normal in times of divided government—no matter which party is in power,” he wrote. “If every committee chairman is going to have this unbounded authority, this Court should be the one to say so.”

Last month, a federal appeals court ruled against the President and allowed the subpoenas after finding that the House committee had a legitimate legislative objective to obtain the information.

“Legislative subpoenas are older than our country itself,” wrote Judge David S. Tatel for a three-judge panel of the US Court of Appeals for the District of Columbia Circuit. “Presidents enjoy no blanket immunity from congressional subpoenas.”

He added that the challenged subpoena seeks financial records “totally unrelated” to the President’s official actions, and that the committee was engaged in a “legitimate legislative investigation.” The court noted that every President who has served since 1978 has agreed to turn over financial disclosures and that asking for financial records would not impair the President from undertaking his official duties.

Trump’s Supreme Court filing was prompted after a larger panel of judges on the appeals court announced that it would not review the panel’s decision. Three members of the court — including two Trump nominees — dissented from that decision.

“The Constitution and our historical practice draw a sharp line between the legislative and judicial powers of Congress,” wrote Judge Neomi Rao, one of the Trump appointees. “By upholding this subpoena, the panel opinion has shifted the balance of power between Congress and the President and allowed a congressional committee to circumvent the careful process of impeachment,” she said.

The court said that the subpoena would go out within seven days.

It is that deadline that prompted Trump on Friday to ask the Supreme Court to put that decision on hold for now while it prepares papers asking the justices to add the case to this term’s docket.

Although the justices are already considering a separate case filed Thursday that concerns a similar subpoena, that case is more narrow in some ways because it involves a New York investigation that lacks the broad separation of powers element of the House case.

“Whatever the justices decide in the New York case will likely be good for that case only, whereas the dispute between the President and the House Oversight Committee has far broader implications not just for the current impeachment process, but for the separation of powers more generally going forward,” said Steve Vladeck, CNN Supreme Court analyst and professor at the University of Texas School of Law.

Critics of the President say that the Supreme Court has long recognized that Congress has the authority to subpoena materials relevant to a legitimate legislative inquiry.

“The Oversight Committee’s request for Trump’s financial records falls well within that precedent,” said Ashwin Phatak, appellate counsel at the Constitutional Accountability Center, a group that sides with the House in the dispute. “Given President Trump’s many complicated business interests, the documents the committee is seeking could help Congress decide whether to strengthen financial disclosure laws and impose new restrictions on presidential conflicts of interest.”