Note, Wesley Clark, was talking about running for POTUS while he was still EUCOM Actual. He (being a "close personal" friend of the Clintons expected their organization to support.., him) Of course this was before President Clinton fired him... That said, as long 9/11 happens he's going to run (and a lot of former subordinates are going to be talking/venting to the Press...).
AS for the original questions, without the Iraq invasion, they'll likely focus more than they did OTL on; 9/11, "Bush let it happen...", mis-managing Afghanistan, AND blaming the Bush administration for NOT resolving the Iraq situation... (remember Northern and Southern Watch, Oil for Food and the associated Oil smuggling... no invasion means all that's still going on). I wouldn't be surprised if the Democrats also claim Iraq did help AQ, with no invasion, Iraq will still be the favorite retirement location of Senior-citizen-wanted Terrorists and the world number 1 provide of counterfeit Passports, US dollars and other papers/IDs.
Break, the one thing most forget when the "What if no Iraq invasion question" is raised, is that Iraq was a problem and issue before we invaded.... Remember the actors, activists, leftist politicians who spent the late 90s 2000-03 traveling to Iraq to complain about the "starving children"... and how it was the U.S./U.K.'s fault, and get their suitcase of cash!
Something was going to come to a head (Allied Pilot(s) shot down and captured, a fire fight on an Oil (and/or weapons) smuggler..... And if it's 2003-04 it will be the biggest impact the election....