According to this column by Tom Friedman of the New York Times, the war in Afghanistan showed that "most NATO countries have fallen so far behind the U.S. in their defense spending and modernizations, they really can't fight alongside of us anymore". While NATO still exists, "The old NATO has been replaced as a military alliance — not by the expanded NATO but by a totally different NATO. The "new NATO" is made up of three like-minded English-speaking allies — America, Britain and Australia — with France as a partner for peace, depending on the war."
This article shows this new military alliance at work. It describes the blockade of Iraqi oil in the Persian Gulf by the Australian, British, and U.S. Navies.
Meanwhile, the U.S. Marines are training in Djibouti, a small nation in the Horn of Africa that used to be a French colony. This New York Times article describes a recent U.S. Marine amphibious warfare exercise there.