The United States is currently engaged in three wars in the Middle East – in Afghanistan, Iraq, and now Libya. The United States has bases all around the world, in more than 150 countries. It has tense relations currently with North Korea and Iran, and has never ruled out military action.
The war in Afghanistan, when it began in 2002, had very strong support from U.S. public opinion, and indeed a great deal of support in other countries. The war in Iraq had almost as much support from U.S. public opinion when it began in 2003, but a lot less support in other countries. Now the United States is halfway into Libya. Less than half the U.S. public is supportive, and there is very much opposition in the rest of the world.
The most recent polls in the United States show opposition not only to the Libyan operation but now to remaining in Afghanistan as well. Pollsters are talking of “war-weariness,” as well they might, since it is hard to argue that the United States has been victorious in any of these conflicts.