Constantinople had not fallen to the Turks in 1453 it can be presumed that the city would have proven to be a thorn in their side (and Russia’s) for centuries to come. The city controlled the access to the Mediterranean from the Black Sea and it would have been able to make both countries bend to its will simply to use the Dardanelles
Because there were messages intercepted from Germany to Mexico, telling Mexico to join the war and attack the United States. I hope this helps :)
They feared being invaded and threatened by NATO because of NATO's exercise of nuclear capability.
