Why Poland for block 3?
If either Russia or Iran is trying to hit America the obvious way to throw missiles is over the pole since that's the shortest Great circle route. Radars at Fylingdales, Thule or in Alaska make sense since they are able to look at the tracks side on. GDMs in any of these places don't seem sensible since they're a long way to the side, meaning even bigger missiles are needed and the longer flight time makes a timely response more problematic.
Poland, OTOH, is further off track than Fylingdales or Thule because its further south. GDM missiles would have not only further to go but would have a stern chase, giving lower approach speed and so much less impact energy, which varies as the square of the impact speed.
So I really don't understand the benefit of radar in Poland, let alone putting GDM stuff there. Unless, of course, the real purpose is to piss Putin off and start WW3.