Hamas isn't threatening the U.S. IF we need to go to war against all terrorist groups, regardless of whether they've targeted the US, why don't we start in Northern Ireland? The IRA - and the protestant paramlitaries - have both killed Americans who happened to be present at their bombings. (Just as Hamas has killed Americans who happened to be present at their bombings)
No, I say we go to war only against groups -- or their suppliers -- who have attacked, purposefully, the US or its interests directly. That includes OBL, but Saddam isn't supporting him.