Start with the rules.
The Vienna Convention on Diplomatic Relations of 1961 is an international treaty that defines a framework for diplomatic relations between independent countries. It specifies the privileges of a diplomatic mission that enable diplomats to perform their function without fear of coercion or harassment by the host country. This forms the legal basis for diplomatic immunity. Its articles are considered a cornerstone of modern international relations. As of April 2014, it has been ratified by 190 states.
Then proceed (bolds, colors, and italics added):
December 29, 2016
Department of State Actions in Response to Russian Harassment
The State Department today declared persona non grata 35 Russian officials operating in the United States who were acting in a manner inconsistent with their diplomatic or consular status. The Department also informed the Russian Government that it would deny Russian personnel access to two recreational compounds in the United States owned by the Russian Government.
The Department took these actions as part of a comprehensive response to Russia’s interference in the U.S. election and to a pattern of harassment of our diplomats overseas that has increased over the last four years, including a significant increase in the last 12 months. This harassment has involved arbitrary police stops, physical assault, and the broadcast on State TV of personal details about our personnel that put them at risk. In addition, the Russian Government has impeded our diplomatic operations by, among other actions: forcing the closure of 28 American corners which hosted cultural programs and English-language teaching; blocking our efforts to begin the construction of a new, safer facility for our Consulate General in St. Petersburg; and rejecting requests to improve perimeter security at the current, outdated facility in St. Petersburg.
Today’s actions send a clear message that such behavior is unacceptable and will have consequences.
From Out of the Past (Moscow Has Played Rough)
“Family members have been the victims of psychologically terrifying assertions that their USG (U.S. government) employee spouses had met accidental deaths,” the embassy reported. “Home intrusions have become far more commonplace and bold, and activity against our locally engaged Russian staff continues at a record pace.
“We have no doubt that this activity originates in the FSB. Counterintelligence challenges remain a hallmark of service at Embassy Moscow.”
The British and American governments are acutely aware of the FSB’s campaign of intimidation. But neither has publicly complained about these demonstrative “counter-intelligence” measures, for fear of further straining already difficult relations with Vladmir Putin’s resurgent regime. Putin, a former KGB lieutenant colonel, was head of the FSB.
British sources admit they have files “five or six inches thick” detailing FSB break-ins and other incidents of harassment against Moscow embassy staff. “Generally we don’t make a fuss about it,” one said. So pervasive is the FSB’s campaign that the British government is unable to staff fully its Moscow embassy. The intrusions are designed to “short-tour” diplomats so they leave their posts early, the source said.
But many of the recent acts of intimidation by Russian security services have crossed the line into apparent criminality. In a series of secret memos sent back to Washington, described to me by several current and former U.S. officials who have written or read them, diplomats reported that Russian intruders had broken into their homes late at night, only to rearrange the furniture or turn on all the lights and televisions, and then leave. One diplomat reported that an intruder had defecated on his living room carpet.
https://en.wikipedia.org/wiki/Zersetzung (East German Psy-Ops)
From the Russian Section