Or something of this nature that minimizes their influence on decisions of war.

You vote for it, you go.

... simplistic and would insure that the US would lose every conflict it engaged in.

Really, I can't tell you what an awful idea that is.

Defense is a different story.

You can't think of a situation that would potentially require military force other than a physical invasion of our borders?

How many of our wars/military "interventions" in the last 50 years were truly justified?
Let this inquiring mind know? Certainly the one going on when I served wasn't.

You ask the right question.

What does the historical record after World War II say?

USG has not defended, it has aggressed.

Halliburton and Blackwater and the neocons and the oil companies probably enjoyed Iraq, but the people of this country lost that war by having been involved in it at all.

The price they paid is not as great as that imposed on the people of Iraq, of whom hundreds of thousands died and millions were wounded, displaced, impoverished and poisoned, in our name. But even beyond the moral atrocity of having been involved in crimes against humanity, assuredly the American people won nothing by this war of aggression. They lost a few thousand lives and trillions of dollars in wealth, so that the worst among them could profit.

The United States government shouldn't be starting any conflicts, that is the point. The US military should have the function of defending the United States, for which it needs a budget of about 10 percent of the current amount (at most, unless you think Mexico and Canada pose a threat.) Another 10 percent could be legitimately devoted to emergency response in real disasters.

The rest is imperialism, and it creates the very enemies that we are then told pose the threat against which we go to war.

World War II was the last one in which the U.S. itself was actually under threat. Even the Korean War is kind of muddy.

The rest of the wars and interventions were strictly for U.S. corporate interests.

The cover story about the Vietnam War being for the purposes of saving Southeast Asia from Communism never quite rang true, but the motives seemed puzzling otherwise. Then, just a couple of years ago, there were reports of oil fields among the Spratly Islands between Vietnam and the Philippines, and I thought, "Uh-huh."

And no, 9/11 doesn't count, because it wasn't a COUNTRY that perpetrated that atrocity. It was a gang of criminals who happened to be present in a country that offered to turn them over to us.

Here's my amendment:

1. No American military troops may be deployed overseas nor may any military attack be launched upon a foreign country from within the borders of the United States without a 2/3 vote of both houses of Congress.
("What about a surprise attack by a foreign power?" you ask. Note that Congress managed to meet after Pearl Harbor and pass a formal declaration of war, and this was during a time of much less developed communications and transportation. Even if the attack occurred during a recess, no Congresscritter is so far away from Washington that he or she couldn't come back for an emergency session in 24 hours.)
2.Such a declaration of war shall automatically trigger a nationwide draft of male and female citizens between the ages of 18 and 25, starting with the first and second-degree relatives of the president, the White House staff, the Cabinet, and the members of Congress.
(During World War II, President Roosevelt and most members of Congress had close relatives in the armed forces. During the Iraq War, only one Congressman did. If the Congresscritters do not think a war is important enough for their own children and grandchildren, nieces and nephews to fight, then it should not be fought. Would Bush have started the Iraq War if it had meant that Jenna and Barbara would be headed for boot camp?)

A thoughtful and interesting proposition.

Nothing wrong with Congress actually do its job and formally declare war. Unfortunately your second point is unconstitutional because of the prohibition of bills of attainder and also the equal protection clause of the 14th Amendment would come into play

since the end of WWII, but won't admit that its an empire.

It's a bit impractical to hold a national referendum in some cases. For instance, if a hypothetical country was in the process of launching missiles or what have you in the US's general direction.