President Donald Trump’s decision to share with Russian officials highly classified information provided to the United States by an ally could chill cooperation with partner intelligence services, particularly if it becomes a routine occurrence.

The Washington Post reported Monday that the president divulged sensitive data about an alleged Islamic State plot to the Russian foreign minister and ambassador during a meeting in the Oval Office last week. The material was given to the United States by Israel, according to The New York Times.

“If what’s been reported is accurate, this does breach the understandings we have with intelligence partners as to how you share with a third party information that they have exclusively provided to you,” said Dennis Wilder, former special assistant to the president and senior director for East Asian Affairs at the National Security Council. “If this becomes habit with Trump or routine, then we’ve got a big problem with intelligence partners because they expect the intelligence professionals to tell the president where the lines, are because presidents don’t know those things.”

The long-term impact of the revelation depends on how the administration handles the fallout. If the president’s disclosure to the Russians signals a shift in how the United States approaches its intelligence sharing agreements, allies are certain to be uncomfortable.

The job of reassuring jittery allies would likely fall to the Director of National Intelligence or the head of the CIA or another spy agency, depending on the situation.

“If the answer coming from the Director of National Intelligence is the president can do what the president wants to do, then these countries are going to have to consider how much they’re sharing,” Wilder said.

Democrats and Republicans alike have expressed concerns about the president’s actions, including their potential impact on relationships with partner nations that the United States works closely with on counterterrorism, counterproliferation and other issues.

“Reports that this information was provided by a U.S. ally and shared without its knowledge sends a troubling signal to America’s allies and partners around the world and may impair their willingness to share intelligence with us in the future,” the Republican chairman of the Senate Armed Services Committee, John McCain, said in a statement.

Israel, the alleged source of the shared material, is a close ally, and the U.S. shares a wealth of intelligence with Asian and Western allies, particularly the so-called Five Eyes — Britain, New Zealand, Australia and Canada, in addition to the U.S.

Past protocol

In the espionage world, protocol dictates that if the United States wants to disclose information it received from an ally, Washington should seek that country’s consent before passing the intelligence on to another country.

It is not unusual, current and former intelligence personnel say, for officials to overstep the bounds of their brief and share classified information provided by an ally to a third country. But they stress that not all “spills,” as such instances are called in intelligence jargon, are created equal.

If a spill only contains non-attributed information, it’s problematic but not a serious problem. If, however, a spill to another spy service contains the source of the intelligence, it’s a big deal because the agent or source of that information would now be in jeopardy.

In the case of Trump’s apparent spill, it’s unclear which category it falls into. National Security Adviser H.R. McMaster said Tuesday that the information the president shared was “wholly appropriate,” and he stressed that no sources or methods were disclosed. Trump didn’t even know the where the information came from, McMaster said.

McMaster’s remarks, however, have failed to clear the air, even on the Hill, where the leaders of the Senate Intelligence Committee, Sens. Richard M. Burr, R-N.C., and Mark Warner, D-Va., were trying all day Tuesday to speak with administration officials.

“What we’re attempting to do is to have a conversation with an individual or multiple individuals at the White House who were part of the meeting that the president had with the Russian foreign minister and the ambassador. We’d like to understand what was said,” Burr told reporters.

He stressed that the president “has the right” to discuss intelligence, but he also noted that “there is a point that you cut that off with foreign leaders, especially when sources and methods are involved.”

Warner said he’s seen reports that there may be transcripts of Trump’s conversations with the Russians, but he said if there is that the committee would like to see a redacted version of it.

Normally, if the White House wants to disclose intelligence material that it has received from an ally, there’s a standard process known as sanitizing. The U.S. intelligence community will contact the allied agency and secure its permission, and then a sanitized version of the information can be passed on.

“If that procedure can’t be reinstituted, then our understandings with other services are in jeopardy because we expect that of them,” Wilder said. “If one side reduces intelligence sharing, the likelihood is the other side will as well. So it can reduce the amount of intelligence sharing both ways.”