"Giving up the Canal" was a good idea. Even in my history classes (which were "America rah rah", back in the 70s), we learned about the Canal as part of "gunboat diplomacy". Basically, we had no navy to speak of, and we were concerned about European aggression because we were so prosperous. So we -quite literally- bought a navy for cash. Shiny new battleships, state of the art (for that time). There was some politics about separating the land from Colombia (since they didn't want us digging a canal), and giving it to Panama (which were happy to have us dig a canal). Then we sent our new battleships to blockade Colombia, basically saying "we're going to dig now".

I doubled-checked my memory, and it was pretty close. For more, read here:

en.wikipedia.org - Panama Canal

That kind of strong-arming and colonialism is not really appropriate today.

Panama wasn't happy about our "ownership" after the WWII, which ended with a treaty signed by Carter that would turn over the Canal to the Panamanians so long as they guaranteed neutrality of the Canal in perpetuity. (Which, if they go back on, then gunboats might be appropriate. We already know we can do that; ref. Noriega.)