Besides the examples above, could Portugal get involved on the side of the British during the American Revolutionary or 1812 Wars or the Confederates during the Civil War [with British support]?
How about a Portugal on the side of the Central Powers?
And during the Cold War, a Portugal that goes totally communist and declares its support for the Soviet Union blatantly after 1975 followed by a large scale WW3 does the solution.
1) The Portuguese were a bit too distant to
genuinely get involved in any of the early wars against the US, so both the Revolutionary War and 1812 are out of the picture. Also during 1812 Portugal had bigger problems (namely the metropole being under French occupation). For the Civil War you'd first need to get London to support the CSA, which is harder than a lot of people on here believe, so that is unlikely as well.
2) Portugal as part of the CP... Nope. While relations with the British went a bit sour after London denied Lisbon the so-called "Pink Map", its relations with Germany weren't rosy either, primarily due to the fact that Portugal felt threatened by the Germans (rightfully so, considering the partition proposals...).
3) A Cold War scenario is the most plausible one but most likely it'd be a proxy war with a or multiple pro-US governments fighting the "legitimate" Socialist government. But I think that's too late for OP, so let's disregard that idea
