http://www.cbsnews.com/stories/2011/10/07/501364/main20117202.shtml?tag=cbsnewsSectionContent.2
Leaving out our Continental Indian Wars, historicly matches is 2nd longest military conflict (with astericks)
1898-1913 Phillipines
1963-1973 Vietnam: This is based on Johnsons massive military buildup, actual involvment is much longer but seems in today's lingo it only counts if there are "combat boots on the ground"
2001+ Afghanistan
2003-2011 Iraq
Now the astericks...inclusion of deployments in countries of past military conflicts?
Western Europe: 1941+
Japan: 1945+
Korea: 1950+
Middle East: 1991+