Worse still, the intelligence in question was reportedly given to the United States by Israel. As with almost all such intelligence sharing, Israel would have expected the information not be shared with others.
Could Trump's loose tongue jeopardize the United States' web of intelligence partnerships? While US allies may proceed more cautiously, perhaps withholding their most sensitive intelligence and doing more to disguise sources, they may not want to disrupt a relationship from which they gain a great deal.
Publicly, Israel has brushed off the issue. Israel's ambassador emphasized
that "Israel has full confidence in our intelligence-sharing relationship with the United States," while the defense minister praised "deep, meaningful and unprecedented" cooperation. But despite these reassuring words, Israel's national security officials will be concerned about two things.
One is the future of their source, whether it was a human agent inside the Islamic State or a method for intercepting the group's communications. If the Russians deem such a source to pose a risk to their military presence in Syria, they might seek to disrupt it. Israel will also fear that Russia may pass on the information to its allies in Syria and Iran, both of whom have an incentive to target Israeli operations. American officials would have been familiar with this risk, not least because they have, in the past, accused
Israel of passing on American secrets to Moscow.
A second risk is that Trump, prone to boastfulness and poorly briefed on the sensitivity of information he is given, does this again. While the United States and Israel have spied aggressively
on one another, they are also exceptionally close partners. They have allegedly collaborated on pioneering cyberattacks against Iran's nuclear program and on the daring assassination
of a Hezbollah leader in Damascus. Some of these joint operations are not only covert, but also clandestine -- meaning the very fact of the operation is intended to remain secret. The risk of further presidential disclosures could make Israel wary about entering into such ventures.
Clearly, the United States' other intelligence partners have also considered this risk. One senior European intelligence official told The Associated Press
that his country might stop sharing information with the United States, as it "could be a risk for our sources."
An outstanding question is whether Trump acted out of carelessness, or because of an affinity for Russia. If evidence points to the latter, then some US allies, such as Ukraine, Poland and the Baltic states, will be especially worried about how US leaks will affect their own national security. Despite their modest size, these countries have excellent intelligence capabilities against Russian targets, which is why they were among the first to detect suspicious interactions between members of the Trump campaign team and Russian intelligence agents last year. If they were to hold back sensitive information from Trump, this would hurt US spy agencies.
In practice, US partners are unlikely to stop sharing intelligence altogether. One reason for this is that many of these countries are likely to receive far more intelligence from the United States than they give up. This is especially true of the so-called Five Eyes alliance, made up of the United States, Canada, United Kingdom, Australia and New Zealand.
To take one example, between 2009 and 2013, the National Security Agency provided its British counterpart, the Government Communications Headquarters, or GCHQ, with £100 million
and 60% of its high-value intelligence.
While these relationships are two-way streets, they are heavily weighted in favor of the larger, wealthier American agencies. As one GCHQ document noted
in 2010, "we need to keep this relationship healthy."
Outside the Five Eyes, Jordan and Pakistan both received over $1 million
from the NSA in a single year, according to documents leaked by Edward Snowden, and probably receive access to information and technology that would otherwise be beyond their grasp. For now, it's likely these countries will judge the benefits of the relationship to outweigh the risk of leaks.
What we may see is that countries are more careful about what they share. Knowledge of high-value human sources has always been tightly controlled, even within the closest alliances. After Britain recruited KGB Col. Oleg Gordievsky in the 1970s, it shared the information with the CIA, but withheld its source until the agent's defection a decade later.
Agencies can also lie about their source. In the Second World War, early British decrypts of Germany's Enigma machine were disguised as reports from fictional human agents and, in the 1970s, the CIA even disguised
one intercept as a report from "an elderly Tibetan horsekeeper." This is not without its problems, as it can affect the way in which policymakers -- including the President -- weigh the importance of the intelligence, potentially skewing policy.
Trump's disclosure is not going to cause intelligence sharing to dry up, but it may well cause American partners to tread more carefully.