When Operation Torch was launched in November of 1942, both Dwight Eisenhower and George Marshall seemed inordinately worried that Spain was going to suddenly enter the war on the German side and attack Gibraltar, or perhaps attack the American landing force in Morocco out of Spanish territory on the African side of the strait. When he wrote out a list of ten things he was worried about as the operation unfolded, Eisenhower wrote "Spain is so ominously quiet" as his chief concern. Many troops were later kept back in Morocco and western Algeria to guard against a possible Spanish attack, even as the campaign in Tunisia unfolded.
Why this attitude towards the Spanish? Their concern seems extremely excessive. If the Spanish weren't going to enter the war in the summer of 1940, why would they do so in the fall of 1942?