To liken the "War on Terror" to WW2 is absurd. Even the phrase "War on Terror" was an invention to capture the hearts of the media guys so it could all be easily grouped under one banner on CNN and Fox. Interestingly here in the UK news items in the middle East are either under Afghanistan or The War in Iraq.
Israel tries to align its actions against Hisbullah (not sure on spelling) as part of The War on Terror but the US reporting doesn't tend to uphold that view

To my mind AKSW makes a good point - if the Northern Ireland peace process collapses can we expect the 101st Airborne in Belfast hunting Republican or Unionist leaders ?? Are there US forces in Sri Lanka hunting the Tamil tigers........ perhaps a few Rangers in Nepal looking for Communist rebels .....???
The "War on Terror" seems to have a pretty parochial mission and it's becoming more and more so. No one believes that Al Queda or any other Islamic extremist group is justified or shouldn't be faced but just how broad will the US administration actually take this "Terror" definition ??? What about Greenpeace activists - the French government had their own view on that.
As a Brit I'd be interested whether any Irish-Americans on the BBS here think that a Republican setting off a bomb is a terrorist or fighter for a united Ireland ???