I couldn't find the exact figures, if anybody knows, of how many Soviet ICBM's are still targeted in this direction or how many may have been stashed according to some rumors, but I think most would agree that the Soviet ICBM's are the greatest potential threat, and will continue to be so until there is an adequate missile defense or a preventative first strike (which I would not advocate). The Soviet Army might be some threat to Europe if they did not starve to death getting there.

After the Soviet missiles, I think that the Chinese Army
comes up next on the list.  I did not realize that China has
a potential army (from references, men 18 to 49 years old) of at least 200,000,000 by now.  That's two hundred million "march-able" men.  With an additional ten million men reaching 18 years old every year. They could waste
ten million men a year without reducing the size of their manpower reserve.  However, it would be a logistical problem for them to just march over here to take over.  But over time, with enough exchange students and COSTCO shipping containers and chinese restaurants, it would only be a matter of time.

Thirdly, a closer, more realistic potential threat would be for Mexico, lead by the Marxists most likely to take over
rotting Mexico in the next ten years to combine with Cuba providing some distraction by invading Florida, formally, and perhaps using some of the nuclear missiles that may still be hidden from the Kenedy-Kruschev days...while Comrade Pancho Villa Zapatista instigates massive mexican-gang-led riots in southwest urban centers to distract the national guard while the balance of at least thirty million soldiers in a Cuban-Mexican-Immigrant front moves the US border
north to Frisco-Denver-Oklahoma City. 

As Tom Chittum pointed out in "Civil War Two", with Mexico as a base to the south and with majority pockets
of "friendly nationals" supporting the guerrillas beyond the front and with some strategic aid from a friendly foreign power (in this case Red China) it would be strategically
and demographically most likely - especially if pulled off
at some future time when the US military is further weakened by the traitorous globalists and are off on some peace-keeping mission in Kosovo, Kuwait, or the Congo.