WWII was a “declared war” with nations named as enemies; have we done that since then?
I get your point, but totally agree with it. I think Congress lacks the backbone to declare war. And even if we did, I have doubts that we would do what was necessary to win. The one case where we did "win" was Iraq War II, where we deposed Saddam and brought about regime change. However, I think almost no one would call what followed a true victory. Grenada and Panama might be other, smaller scale, examples.
It was also the last time that the Congress utilized the War Power correctly:
"...the President is hereby authorized and directed to employ the entire naval and military forces of the United States and the resources of the Government to carry on war against the Imperial Government of Japan; and, to bring the conflict to a successful termination, all the resources of the country are hereby pledged by the Congress of the United States.
The thing with "war" and "Congress" is this: Congress (in the original scheme) represents the People (House) and the States (Senate). Without the agreement of both, wars cannot be won.