Spies in the movies and on TV are one-man (or woman) bands. They parachute in, do some dramatic stuff, and get the goods all by themselves.

But in real-life spying, especially the counterterrorism kind, that’s not how things work. When it comes to the fight against ISIS, the US relies heavily on information from deep-cover agents from countries like Turkey, Jordan, the United Arab Emirates, and Israel.

President Trump has just seriously damaged those relationships. The Washington Post reported that Trump shared highly classified intelligence with Russian Foreign Minister Sergei Lavrov during his visit to the Oval Office. The New York Times then reported that the information came from an Israeli source who has in the past provided some of the most valuable intelligence about ISIS.

Watch the video above to learn more about how these information-sharing relationships work, and why they’re so important for fighting terrorism.