There are a few things in life that cannot be refuted: The Beatles will always be Gods in the Rock 'n Roll, Morgan Freeman has the best voice ever, and men will always lust after beautiful women. Another undeniable truth is over the past few decades, the nature of war has changed. The way formal nations wage war, the way rebels revolt against their governments, and the politics involved with international war, all of these things have changed dramatically. It is a lamentable that World War II was the last formal war the world will ever see.
The US never formally declared war with Korea in the 50s, not to mention Korea was not the true opponent to the US in that conflict. The Korean War was a part of the Cold War. We were fighting the USSR, the communists. We did the world a favor not going into formal war with the USSR. Two nuclear superpowers with the ability to destroy the world a hundred times over, and this was less than a decade after the US dropped The Bomb to end WWII. Not to mention, there was no true casus belli to justify war between the two nations. There was nothing tangible to gain. No land, no capital, nothing. Just the Americans vanquishing the evil commies.
The Vietnam War was also never declared, nor was it the United States against the Korea. It was the US trying to eradicate the Viet Cong in a jungle war; another installment of the Cold War. Nam was about three things: helping out the Vietnamese get rid of the Viet Cong, stopping the spread of communism, and the US getting to test out new military assets. It was in Nam the US gave up on close range charged particle beam (think star wars laser rifle) based weapons because the batteries for the things were the size of a coffin and were prone to over heating. The Air Force had mixed results from Nam. The new F-4's were awesome aircrafts for precision bombing, as well as carpet bombing the hell out of a target, but the Viets had the Russian MiGs. Jets that were superior in air superiority. There was some issues there. The rest of this is an argument for another day, the point is the US had no real reason to be in Vietnam, other than the Cold War.
The Gulf war, less than 20 years ago was another informal war Congress never declared. With the Cold War over, there were real commodities at stake in this conflict. Iraq invaded Kuwait, and we all know the rest of what happened. Here was the truth behind it. Iraq was committing horrible international war crimes as well as destroying global oil reserves. With the US being seen as the world's most powerful military force in the history of the planet, we were almost expected to do the majority of the work And, we did, with much help from Saudi Arabia, the UK and Egypt. The Gulf War was a humanitarian conflict as well as the US protecting the world's oil interests.
Before the Gulf war there was Grenada ('83), and the Tanker War in Iran ('87-88), then the thing with Panama ('89). After the Gulf War there was the US Intervention in Somalia ('92-94), then the intervention in Bosnia ('94-95), the the US occupation in Haiti ('94 and then again 10 years later in '04) and so on and so forth.
So, what I propose is a change in how countries wage war and what can and cannot be allowed to be done by individual policing nations and the UN. I do not know are the world's leading experts in war, but I guarantee you anything the Chairman of the Joint Chiefs has got to be one of them. Ask the previous 4 or 5 Chairmen and they will tell you, they cannot tell when we are at peace nor when we are at war. War has changed.