At a recent conference on "The Unending Korean War" at New York University, the keynote speaker, Bruce Cumings, a history professor at the University of Chicago, explained that the UN provided the means for the then US President Harry S. Truman to bypass the US Congress in intervening in the Korean War.

Under Article 1 Section 8 of the US Constitution, the power to declare war is vested in the Congress. But in June 1950, Truman did not go to Congress for a declaration of war.

Instead, Cumings explained, "The UN was the legislature that the US knew they would get a majority vote in." At the time, the Soviet Union was refusing to participate in the UN Security Council, and the Chinese seat was held by representatives from Taiwan.

There would likely have been a challenge to a declaration of war in the US Congress. Hence it was the UN that provided the appearance of legitimacy for the US role in the Korean War, explained Cumings.

The Korean War, according to Cumings, was the first time the US went to war without a congressional declaration. "The US executive branch hasn't gotten one (a congressional declaration of war) since," Cumings noted.

The current case ofLibya is the most recent instance of a president going to war without the needed constitutional authorization.

Instead of US President Barack Obama going to the US Congress to ask for a declaration of war against Libya, he went to the Arab League and the UN Security Council, explains Dennis Kucinich, a Democratic congressman from Ohio.