During the Cold War, were Soviet naval vessels allowed to use the Panama canal?
I'm aware that no Soviet warships happened to use the canal during the Cold War. Was there a rule aganst them transiting the canal, or were they free to do so, even if none actually did?
For example, if any Soviet warships went between Atlantic and Pacific by going via a longer route, this would be evidence that they would have used the canal, but that they weren't allowed to.