Washington: As a convoy of Russian armed forces more than 50 kilometres long edges towards Ukraine’s capital, it begs the question: what will it take for the West to take direct military action against Vladimir Putin’s aggression? While the US and its allies have condemned Putin’s “unprovoked and unjustified” invasion, President Joe Biden has made it clear he will not put American troops into Ukraine and battle Russia directly. Maxar Technologies “That’s a world war when Americans and Russia start shooting at one another,” he told NBC’s Lester Holt this month, when asked what kind of scenario would prompt him to put boots on the ground in Ukraine.