Yep. Three or four freighters. Three or four non miniturized war heads. Three or four two-bit missiles. The Norks will be able to do it soon enough. The Iranians will be able to do it in a bit. Any present nuclear power in the world can do it. And the delivery systems are not in orbit. Low or otherwise. The only defense presently is our ABM system. And the dims will destroy that soon enough.
And this is supposed to be simpler to do than detonating a suitcase nuke in an urban center? We must have some different definitions of “simpler.”