Climate change and drought have caused big problems for the canal. There's less water available to keep the locks full. That means substantial traffic delays for shipping through the canal. It also increases costs for whoever is operating the canal. So canal transit fees have to go up.

At some point, it will become quite burdensome to keep the canal operating at even a break-even cost/income basis.

So, maybe Trump can have his wish. Soon, though, he'll wish he hadn't wished for it, I expect.

while all fees are to be deposited in The King's petty cash account,

Watch my lips move, not my bitcoin haul.

some mood music to Manifest Destiny by:

...and he'll want Cuba as well. We struck a deal with the Russia to never invade or aid anyone else on that endeavor. We start pushing on that, nukes will be back on that island in no time. Possibly in Venezuela and Nicaragua as well.

We'll go from a 15 to 20 minute window of warning to practically only knowing when they hit.

One of the goals of the Southern expansionists (they wanted new territories for cotton, and hence slavery) was to annex Cuba as well as other parts of Latin America. They got part of their wish in the Mexican-American war, but, as usual, it wasn't enough. MacPherson discusses this in his Pulitzer Prize-winning "Battle Cry of Freedom"

If Trump used his presidential war powers to do this. What would stop him from doing so?

He’s implied Canada is really the 51st state and Canadians would be happy to pay fewer taxes.