Just to point out, there has not been a single successful ICBM intercept test to this day. There have been cruise missile intercept tests and a single IRBM test. But they mostly operate in atmosphere and are barely over sound speed limit (at least those that were tested against, even IRBM was atmosphere only flight). But even if we look at cruise missiles, tests were successful only when flight path has been predetermined.
Just to stress a point, last December Saudi Arabia tried intercepting an allegedly Iranian SR/MRBM. They fired 5 Patriot missiles at it almost head on. None hit. The missile flew over missile defense battery, reached its target (airport) and blew up close to a runway. Another case was when an anti ship cruise missile was launched at a US ship. The ship launched a volley of missiles and counter measures, but there still is no evidence if anything had an effect or missile simply broke down mid flight. No hits were registered by the ship at least. Real missiles are not synthetic tests. Realistically speaking, no country in the world has technology to shoot down ICBMs with success rates that are above fluke chance. IRBMs are also purely theoretical at this point. SRBM and MRBM interceptions also have a very low success rates, even when targeted by multiple missiles and countermeasures.