Nicaragua was an early favorite for a canal. The French had a significant investment in Panama, although they were not successful in bringing it home. Rather than lose that investment, they successfully "lobbied" for a buyout and US takeover of their canal.
Trump's recent talk about a renegotiation of the canal treaty is probably just that: an attempt at negotiation a lá Trump.
Still, the Nicaragua Canal has has always made sense. A lot of engineering has been done; Their is even a completed EIR. The canal would only have two locks as I remember,, at each ocean exit/entrance. The bottom of Lake Nicaragua is a fine silt, so the canal would probably have to be routinely dredged, Some other problems include the fifty year renewable concession the Chinese negotiated with Nicaragua.
BUT, the Nicaragua canal would be closer, faster, with minimal locking, and could accommodate super wide vessels like US aircraft carriers.
