Yes, the European missile defense system is indispensable, because it is the best current technology available. The European missile defense system allows Europe to respond immediately to threats. Technology in space does not yet offer a viable alternative. With instability in Russia and the Middle East, Europe's missile defense system is indispensable to its peace and security.
Instead of having a missile defense system for Europe to protect against Russian rockets, why not offer diplomatic solutions instead? Russia and other nuclear-armed nations need to simply get rid of all nuclear weapons in the world and then there won't be a need for expensive missile defense systems. Russia may be a hardline nation, but it's not the Soviet Union during the Cold War.