You are mistaken. N. Korea already first possessed several nuclear bombs it developed during the Clinton Administration. Slick Willie was too busy with certain friends to do anything about it.
We know for a fact that Saddam had possesed WMD. In fact Saddam murdered his own countrymen with WMD. Whether he eliminated his WMD before the Iraq war was not something the U.S. could determine with any comfortable degree of certainty without forcibly entering into Iraq, considering that Saddam had previously expelled the U.N. nuclear watchdog from Iraq. As a result, there was every reason and right to be suspicious of Iraq’s WMD program. Saddam was at fault for these suspicions with his expulsion of the IAEA.
Perhaps it is debatable who we should have taken on first, N. Korea or Iraq. Perhaps, since Clinton allowed N. Korea to develop nukes before we did anything, N. Korea was a more difficult situation than Iraq (since it possesed nukes and is within easy reach of Seoul) so we took on Iraq first. This is a consideration for the NSC and the POTUS, not us who aren’t privy to relevant national secrets.
It is completely secondary that Iraq was not involved in 9/11. Iran wasn’t either. Should we do nothing about Iran now (including eliminating from the table the possibility of military action) since Iran wasn’t involved in 9/11?
Also, let us not forget Clinton’s utter failure to respond at all after the terrorists attacked the United States in 2000 with the USS Cole bombing killing 17 U.S. Navy sailors. Unlike in 1998 after the terrorists attacked the 2 U.S. embassies in Africa, when all Clinton could muster was a pre-announced attack on a Sudanese animal pharmaceutical plant for the murder of 12 Americans (and even that was merely to deflect attention from his philandering ways in the news), after the USS Cole Clinton did zilch to the terrorists.
That lack of response by Clinton is what gave Bin Laden the impetus to think he could get away with the 9/11 attacks with impunity and encouraged Al Quida to carry those attacks out directly on U.S. soil.