In March, a former Russian military intelligence officer that sold state secrets to the British government was attacked in Salisbury, England. While he and his daughter survived the ordeal, the international ramifications were swift once the nerve agent used was identified as one of specifically Soviet manufacture, suggesting to U.K. officials and their allies that Russian operatives had conducted the attempted assassination as retribution for the former officer, Sergei Skripal, betraying the Russian state.

The U.K. and a number of its allies responded not only with tough rhetoric but with the weapons of diplomacy: economic sanctions and the expulsion of Russian officials and diplomats from within their nation. Russia, claiming innocence throughout, responded by expelling foreign diplomats from each involved nation in kind.

For the most part, these diplomat expulsions tend to go on without much concern from the general public. It can be difficult to assess the value American officials serve from their offices on foreign soil within the vastness of the nation’s foreign policy apparatus, especially because bureaucracy, while often necessary, rarely makes for engaging headlines. However, many officials operating on foreign soil have another, less publicized, responsibility that comes with direct ties to the nation’s defense efforts: intelligence handlers. When Russia expelled American diplomats from Moscow, they didn’t only set American bureaucracy back, they also dealt a significant blow to U.S. intelligence gathering efforts within Russia as well.

“The Russians kicked out a whole bunch of our people,” John Sipher, a 29-year C.I.A. veteran that previously ran the agency’s Russia program said. “Our station in Moscow is probably really small now and they are under incredible surveillance.”