So, one of government's undisputed obligations is the protection of its population from hostile nations. NATO better be willing to step up and proactively protect the member states and their population.
At what point do 'minor' transgressions become actionable? Like, if Russia was told by NATO reps that the next time any citizen gets assassinated and it is proven they are responsible, or that a Russian damaged NATO cables or whatever that an immediate response will be enacted. Notice I didn't say 'proportional'.
Cable snapped and Russian captain who did it? Tomahawk to an airbase near St. Petersburg. Don't want to go to war? Cut the shit. Period.