"Russia was one of our allies in the last world war."

They didn`t start out that way. And with Putin in charge they cannot be trusted even today.
They were allies with Germany when war was declared on Germany by England and Poland and France in the conquest and splitting up of eastern Europe.  Then Hitler stabbed Stalin in the back.
 Communist Russia and Stalin, it`s murderous leader, only came over to the allied point of view when Hitler broke his deal with Joseph Stalin, turned around and suddenly invaded the Soviet Union through Ukraine.  Communist Russia became one of our "allies" by necessity not by choice. Their existence depended on it.  Germany would quite possibly have beaten Russia to the point of domination, without US aid and assistance that came after Hitler`s betrayal, in the way of loans and supplies and materials sent to Russia from the USA through a very dangerous convoy program to Murmansk.