FILE - In this file photo taken Thursday, March 1, 2018, journalists watch as Russian President Vladimir Putin gives his annual state of the nation address in Manezh in Moscow, Russia. Buoyed by an oil boom, President Vladimir Putin's rule since 2000 has been marked by complaints about corruption and human rights abuse, tension with the West over Moscow's 2014 annexation of Crimea and accusations of meddling in U.S. elections. (AP Photo/Alexander Zemlianichenko, File)
FILE - In this file photo taken Thursday, March 1, 2018, journalists watch as Russian President Vladimir Putin gives his annual state of the nation address in Manezh in Moscow, Russia. Buoyed by an oil boom, President Vladimir Putin's rule since 2000 has been marked by complaints about corruption and human rights abuse, tension with the West over Moscow's 2014 annexation of Crimea and accusations of meddling in U.S. elections. (AP Photo/Alexander Zemlianichenko, File) Credit: ap โ€” Alexander Zemlianichenko

Global spy games just got a little more dangerous with the byzantine poisoning of Sergei and Yulia Skripal in the medieval-era U.K. city of Salisbury. Extraterritorial assassination attempts are usually precisely targeted with the victim attacked in an unmistakable, but quiet, surgical strike. Among developed nations, there is not supposed to be any collateral damage and the attacking nation tries to maintain plausible deniability.

But the Skripal case using the Russian โ€œNovichokโ€ nerve agent just changed things.

The message to double-crossing double agents? There is no place to hide. The message to host countries harboring these defectors? Drop dead. More countries are witnessing targeted foreign assaults and assassinations on their soil in a wanton and reckless disregard for diplomatic norms, innocent bystanders and respect for national sovereignty.

Prime Minister Theresa May is showing both warranted outrage and unprecedented backbone regarding this poisoning. She has rightly noted the attack on the Skripals has harmed British citizens on British soil and exposed a larger citizenry to dangerous toxins. Further, she railed that Englandโ€™s security forces were contaminated, and, most important, that this was a direct attack against her island nation. A NATO consultation may be in the works. Twenty-three Russian diplomats have been expelled. Even deeper retaliation is on the lips of an offended and angered political class.

While President Trump has been characteristically restrained regarding all things Russian, U.S. Sen. John McCain, R-Ariz., stated that โ€œwe must recognize Putin will not hesitate to engage in state-sponsored assassination. He must not be allowed to treat the U.K. or any other nation as a venue for political murder.โ€ Secretary of State Rex Tillerson, too, responded quickly and unequivocally to the attack, saying the poison used โ€œclearly came from Russiaโ€ and that the โ€œreally egregious actโ€ will โ€œtrigger a response.โ€ The response came quickly. He and the departmentโ€™s undersecretary for public diplomacy, Steven Goldstein, were fired.

Russian Foreign Minister Sergei Lavrov said โ€œwe have nothing to do with this.โ€ Tillersonโ€™s gone while Lavrovโ€™s star continues to rise. Where will a post-Rex America stand on Britainโ€™s findings and any of its calls for further action against Russia?

How a post-Brexit Britain and her dwindling Western allies react and respond to this new crisis is going to redefine the unwritten rules of how nations deal with growing, stealthy and murderous incursions on their territory. U.K. actions will help redefine the way national intelligence services behave abroad โ€” both in what is acceptable and how they will act unilaterally in cases where they aggressively seek to protect national security and deeply held secrets. Are defectors off-limits? Does the killing of traitors have a statute of limitations? Are there any applicable norms in a covert world where rules donโ€™t easily apply? Should countries get away with anything as long as they are not caught red-handed?

These are difficult questions. The conditional ethics of covert behavior and intelligence activities are complex and alterable. Thatโ€™s why John le Carre novels, like The Spy Who Came in from the Cold, are so deeply engaging. They force the reader to explore the personal conflicts of patriotic demands and the moral ambiguities of duty-bound action.

Britainโ€™s most notorious double-agent, Kim Philby, was a part of the Cambridge Five spy ring before defecting to the USSR. Whether the Brits tried to kill Philby in Moscow is unknown, but he lived to an alcohol-pickled 76, honored for his Soviet service with the Order of Lenin and the issuing of a five-kopek postage stamp.

Edward Snowden, the former National Security Agency contractor, is a contemporary intelligence asset living in Russian exile. Snowden does not yet have a postage stamp, but he does, so far, get to live securely in an undisclosed location in Moscow. The Skripal assassination attempt must be upping his already high paranoia that โ€œthey will put a bullet in my head or poison me when I come out of the supermarket.โ€ Even former Texas congressman Ron Paul believed that โ€œsomebody in our government might kill him with a cruise missile or a drone missile.โ€

True, American government officials do want Snowden dead, but they want Snowdenโ€™s death to take place in the good old USA, not under cover of darkness in another country. CIA Director and Secretary of State-designee Mike Pompeo has called for Snowdenโ€™s execution โ€” not in Russia, but by bringing him home, giving him a trial, and handing him a death sentence.

The American and British approach to defectors, spies and other wanted criminals or convicted enemies of the state is to actively try to get them back. In the meantime, they get to live out their miserable lives abroad.

Russia thinks differently and is double-daring Western nations to do something about it. Theresa Mayโ€™s Britain just might.

Markos Kounalakis is a senior fellow at Central European University and visiting fellow at the Hoover Institution.