WASHINGTON — A federal appeals court panel on Tuesday appeared skeptical of former President Donald J. Trump’s claim that he has the power to block a congressional subpoena for White House records related to the Jan. 6 attack on the Capitol.

President Biden thinks lawmakers should see the files, producing a clash with his predecessor over executive privilege.

During about three and a half hours of oral arguments, the three-judge panel signaled concern with figuring out what general rule or legal test should govern not just this dispute but any future ones in which a sitting president and a former one disagree over whether to invoke executive privilege over particular documents.

There is no clear Supreme Court precedent to determine what should happen in such a dispute, which arose when the House committee investigating the Jan. 6 assault subpoenaed the National Archives for records showing Mr. Trump’s communications and movements leading up to and during the crisis.

After Mr. Biden declined to invoke executive privilege to block the subpoena, saying it was in the national interest for the oversight committee to see the records in light of the circumstances, Mr. Trump filed a lawsuit seeking to keep the files secret. A Federal District Court judge ruled in November that Congress should get the files, and Mr. Trump has appealed.

At issue before the U.S. Court of Appeals for the District of Columbia Circuit is whether Mr. Trump is so likely to lose the case that the National Archives should be permitted to turn over batches of records to the House committee right away, or whether they should stay blocked while the case is fully litigated.

Both in office and out, Mr. Trump has pursued a legal strategy of stonewalling subpoenas and using the slow pace of litigation to run out the clock on congressional oversight efforts. A lawyer for the House, Douglas Letter, told the appeals court that the judiciary should lift a short-term block so the committee can see the files while its inquiry remains open.

The lawsuit “is interfering with something that is going on right now with immense speed,” said Mr. Letter, who added, “As President Biden recognized, these are key documents that Congress should have, and it should have it right now.”

But lawyers for Mr. Trump argued for a slower process on Tuesday. They said it was important that the weighty issues be fully explored before any files were transferred, since if Mr. Trump won in the courts but Congress had already seen the confidential communications in the interim, the harm would be done.

One of the lawyers, Jesse R. Binnall, offered to do another round of written briefing to flesh out additional issues.

Another lawyer for Mr. Trump, Justin R. Clark, argued that even if the court decided the subpoena met legal standards and that Mr. Biden’s waiver of executive privilege outweighed Mr. Trump’s invocation of it — both of which they contested — the judges would then need to examine the “individual documents in question” before making any ruling.

“Under what authority?” Judge Patricia Millett asked. She and Judge Ketanji Brown Jackson pointed out to Mr. Clark that the court record did not have any filing from the Trump legal team putting forward specific claims that particular files raised special concerns, beyond the general interest in presidential confidentiality.

“Your honor, it’s not there yet,” Mr. Clark said.

The judges appeared to agree that language in a 1977 ruling involving Richard M. Nixon’s White House papers meant that when a current president and a former president disagree about invoking executive privilege, the current president’s views “get extra points on the scoreboard,” as Judge Millett put it.

But Congress, in the Presidential Records Act, gave former presidents a right to file a lawsuit in such a situation — suggesting that the incumbent president’s view should not necessarily always prevail. Judge Robert L. Wilkins in particular resisted arguments by Mr. Letter and a Justice Department lawyer, Brian Boynton, that there was no need for courts to weigh balancing interests in a case where the current president had waived the privilege.

The judges also worked through a series of hypotheticals trying to probe what the general rule or principle should be in assessing any such case that might arise, including a scenario in which a newly elected president declares that it is in the national interest to dump out all of the predecessor’s files as a matter of vengeance.

Mr. Letter, the congressional lawyer, said that an ex-president would have greater secrecy powers when it came to blocking disclosure directly to the public of an administration’s archives, but that Congress was different. He also suggested that the hypothetical scenarios the judges were exploring were unrealistic, saying they could raise the larger question of whether a president was insane and should be removed from office under the 25th Amendment.

Mr. Boynton, the Justice Department lawyer, argued that the dispute over the Trump White House files was an easy one, saying that the court should rule for Congress and the Biden administration without trying to definitively answer tougher questions about the scope and limits of an ex-president’s executive privilege powers under other circumstances.

All three judges on the panel were appointees of Democratic presidents, as was the district court judge who ruled against Mr. Trump on Nov. 9. But Republican appointees control six of the nine seats on the Supreme Court, where the case seems destined to end up.

Mr. Trump’s lawyers asked the appeals court, if it rules against them, to keep blocking the National Archives from providing the disputed documents to Congress for another 14 days to give the ex-president time to appeal again to the Supreme Court.