In the early 1900s, the United States had two options: build a canal across Nicaragua, or, through Panama. The US Senate voted for the Panama option.
Estimates of how much it would cost to build a Nicaraguan Canal ...upwards of $40bn
I looked it up, the Nicaraguan Canal would have been about 170 miles, so $40bn for 170 miles. From a modern day engineering standpoint, putting aside lawyers, environmentalists, government, etc. how hard is it to build 170 miles of canal?