Well, thats funny because I spoke with a recently retired general that told me that Russia knows they are in trouble and they would have a very hard time getting a bunch of missiles past our system. Of course it can shoot down ICBMs. And the "multiple warheads" are upon entry. If you shoot them down in space they can have as many warheads as you want them to have and they won't reach their targets.
Also, Russias missiles are in dire need of maintenance. They have no money, Russia is dirt broke. Their missiles have been neglected for decades, and I've heard experts say that there is no way to know how many would even launch successfully, but it surely wouldn't be 100%. The USA has kept up their enduring stockpile of weapons in a ready state. Russia has not done the same.
And these are radar guided missiles, not heat seeking so flares and chaffs do nothing.