In this unrealistic hypothetical, yes Russia hosting some shorter range theatre ballistic missiles on Greenland would give the US less warning versus ICBMs in a hypothetical attack. A handful of minutes versus tens of minutes. Russia could always send a submarine off of the coast of the US and launch an attack from there if they wanted minimal warning. Greenland is important to the US for other reasons, missile warning for said ICBMs and economic reasons around rare earth minerals and shipping lanes. Thule Site J is quite important for tracking satellites, ballistic missiles and space objects. It’s important to look at the world from a spherical perspective here.
In this unrealistic hypothetical, yes Russia hosting some shorter range theatre ballistic missiles on Greenland would give the US less warning versus ICBMs in a hypothetical attack. A handful of minutes versus tens of minutes. Russia could always send a submarine off of the coast of the US and launch an attack from there if they wanted minimal warning. Greenland is important to the US for other reasons, missile warning for said ICBMs and economic reasons around rare earth minerals and shipping lanes. Thule Site J is quite important for tracking satellites, ballistic missiles and space objects. It’s important to look at the world from a spherical perspective here.