The attempted murder of former Russian spy Sergei Skripal in Britain poses a fundamental question for governments around the world: Will they demand accountability from Russia for this despicable act or will they turn a blind eye to the first offensive use of chemical weapons in Europe since World War II? While it may be tempting to accept Russian assurances that it is not involved, there is too much evidence to blithely accept Moscow's denials. For wavering governments, another way to frame the situation is this: What would they do if there was a terrorist attack on their soil that employed weapons of mass destruction and threatened hundreds, if not thousands, of innocent lives?

Skripal was a former double agent working in Russia: He was a member of Russian military intelligence (the GRU), who worked for British intelligence during the 1990s and 2000s, until his arrest in 2004. In 2006, he was convicted of high treason and sentenced to 13 years in prison. In 2010, he was swapped, along with other spies in Russia, for 10 Russian spies arrested in the United States. He settled in the United Kingdom and lived quietly until March 4, when he and his daughter, Yulia, were found unconscious on a bench near a shopping center in the town of Salisbury. Both are fighting for their lives and may never regain consciousness or full mental capacity.

An investigation revealed that the two were poisoned with Novichok, a powerful nerve agent that was only produced by the former Soviet Union and later by Russia. Moscow denies any responsibility — calling the charges politically motivated and "a circus show" — and even asserted that it did not make the weapon, despite extensive proof, including admissions by scientists who worked on the deadly agent. No other country is known to have developed the weapon.