This is coolbert:
From Strategy page and the article by Colonel [Ret.] Austin Bay "On Point".
"Is Russia's Nerve Gas Attack in Great Britain An Act of War?"
"The British government has directly accused Russia of using a very sophisticated chemical weapon ---a 'poison gas' in common idiom -- in a failed attempt to murder a former Russian defector and his daughter."
IS THIS AN ACT OF WAR?
YES AND NO DEPENDING ON HOW YOU DEFINE "WAR".
"Putin's Kremlin practises what some analysts call 'gray zone warfare.'"
"Waging a gray zone campaign requires maintaining 'plausible deniability' -- in order to escape retribution, be able to deny responsibility for the dirty and destructive operations."
"Propaganda, crime, covert influence operations, cyber intrusions and old-fashioned bribery are gray zone weapons." Add also sabotage and assassination!
Consider also that: "Novichok -A-230, an 'enhanced nerve agent dispersible as a liquid or powder. Reports claim it is eight times more toxic than VX liquid nerve agent."
ENHANCED TO SAY THE LEAST!!
As to this being an act of war consider this generally agreed upon definition: "The essence of war is a violent struggle between two hostile, independent, and irreconcilable wills, each trying to impose itself on the other."
WAR CONSISTS OF TWO HOSTILE PARTIES IN CONFLICT! NOT SO IN THIS CASE? ONLY ONE PARTY AT FAULT HERE!