City of Heroes/Headscratchers

Why doesn't the United States Government respond to Arachnos, Nemesis and Rikti presence in Paragon City?
Lord Recluse is the head of state of the Rogue Isles, and Arachnos is his military force. Any Arachnos presence on American soil is, by any reasonable determination, a foreign invasion and an act of war. The Federal government is obligated to dispatch troops to combat such an incursion.

Nemesis may not be a head of state any more, but he's still deploying a huge private army in an attempt to re-occupy a nation that he took over in the 19th century. This guy succeeded once already -- the Army ought to be be hunting down his little brass soldiers from door to door, and the Navy should be shelling and torpedoing whatever Age of Steam craft he's using to transport them into Rhode Island.

And the Rikti -- explicit alien invaders occupying entire neighborhoods, killing humans with gay abandon. Certainly they deserve a massive military response rather than the laissez-faire policy of letting street-level superheros handle them on a squad-by-squad basis.

Why is the Federal Government maintaining a complete "hands off" policy about Paragon City? Did the Rikti invasion so devastate the rest of the country that the government can't do anything? Is Paragon City the best-off place in North America, even with aliens, Prussians and spider-themed special ops teams on every corner?