WASHINGTON - Democrats responded with aggrieved fury when former President Trump was found in possession of classified documents that should have been turned over to the government when he left office. Then disclosures that President Biden also mishandled secret papers set loose a Republican “well, what about” roar.

Now, with another discovery of classified documents, this time at the home of Mr. Trump’s vice president, Mike Pence, the partisan finger-pointing seems to be melting into a chorus of mortification from Democrats and Republicans.

The highest U.S. secrets, it now appears, are not necessarily safe with the highest officials. Not when they’re in the hands of Mr. Trump, who disdains the rules and customs of government, and not in the hands of President Biden and Mr. Pence, who subscribe to them.

“What the hell’s going on around here?” asked Sen. Marco Rubio of Florida, top Republican on the Senate Intelligence Committee, when asked about Mr. Pence.

“Obviously there’s a systemic problem in the executive branch,” Sen. Rubio said. “We’re talking about two successive administrations from two different parties, with officials at the top level having, in their possession, documents in places that they don’t belong.”

The Democratic chairman of that panel, Sen. Mark Warner of Virginia, had tart advice for all ex- presidents and future ones regardless of party: “Go check your closets.”

The latest disclosure came from Pence lawyer Greg Jacob, who informed the National Archives — the proper place for such material — that classified documents were found in Mr. Pence’s Indiana home last week.

Mr. Jacob said an apparently small number of papers were inadvertently boxed and transported to the home at the end of the Trump administration and came to light when Mr. Pence, prompted by the discoveries in President Biden’s home and pre-presidential think-tank offices, asked lawyers to see if he had some, too.

Special counsels are investigating the Trump and Biden episodes. In all three matters, the significance of the classified material and whether its mishandling breaches national security is not publicly known. But it is clear that some of the documents retrieved at Mr. Trump’s Mar-a-Lago home in Palm Beach, Fla., were top secret.

Aides to President Biden, a Democrat, say they cooperated quickly and fully when such material was found at a former office in Washington, though they waited for months to make public what had happened.

In the Republican-controlled House, Rep. Mike Turner, R-Ohio, a contender to lead the Intelligence Committee, said he will ask for the same intelligence review and damage assessment in the Pence case as he did in earlier discoveries.

“It is a serious matter for any government official to mishandle classified documents,” Rep. Turner said.