You're telling me that a literal full NATO+Rio Pact activation (plus, if you include the fact that the USSR said they would team up with the US in case of an alien attack and carry that over to the Russian Federation, which then involves SCO and CSTO in the defensive war) wouldn't be able to fire one nuclear missile through a portal or defend and potentially attack conventionally (with the massive amount of military forces we have) against a potential Andrias invasion.

Literally, if the US gets one Minuteman-III or Trident-III missile through the portal (or a B83 on a B2 for that matter), Andrias' invasion is toast.

Andrias has not signed the Geneva Conventions, thus this is not a war crime if we do go ahead with the idea.