If Russia or Iran (or ISIS for that matter) want to send nuclear bombs into Europe or even the USA, they won't use missiles. These are expensive and relatively unreliable.

But container traffic is a reliable way of sending stuff around the world and, so long as you can plan a month or so in advance, your weapon will be delivered safe and sound right to the heart of your target.

So missile defense is doubly stupid and reflects an inability to move away from Cold War silliness

keep to the Fen Causeway