The Cold War ended in 1991 after the Soviet Union fell apart. Since then, Russia's economy paralyzed, and the United States is three trillion dollars in debt, and both counties were weakened by the Cold War because of military spending. To have world peace does not mean that United States should increase its military strength. The Realist theory would argue that military strength is important to maintain peace both domestically and internationally. Even though the United States as the only superpower remains in certain perspective, the U.S can not be the peace keeper for the whole globe and every state on it.
First of all, there are more than two hundred sovereign states in the whole world, and to have world peace requires every sovereign states' effort not only the United States but also every other states. A good example was the coalition force led by the United States under UN command which defeated Iraq's invasion army in Kuwait City in 1991.
But the United States still respected Iraq's sovereignty under international rules. That was probably the reason why President Bush did not order the U.S army to invade Iraq after the U.S led coalition force expelled Iraq's force in Kuwait. Another example would be when Iraq's government massacred thousand of ethic minority Kurds when the Kurds rebelled against Iraq government in northern Iraq. The United States did not do a lot to help the Kurds because United States and the rest of the countries around the world recognized Iraq as a sovereign state in the international community even though that United States had a large military presence in the Persian gulf area during that time.
More and more, non goverment organizations also play very important roles in world peace. Since 1945, the United Nations, a non government organization, has...