Let's walk...
Well Larry I, for one believe that if the Democrats had backed the President and supported the war instead of telling the terrorists that we were divided about the war and the outcome, it would have been over a long time ago.
...through this, shall we? If Democrats supported SDI we'd be further along than we are to ICBM obsolescence. If GOP'ers supported socialized medicine Hillary would have gotten that done in 1993. If GOP'ers supported the global warming farce, we'd be a signatory to Kyoto. If the enemy didn't fight back, they'd have lost by now. If my Aunt had balls, she'd be my uncle.
We live in a representative republic, not a dictatorship. We have an adversarial political system. Your argument presumes that the right thing to do was to invade Afghanistan and Iraq and that everybody ought to go along, heart and soul, just because you, or the President says it's the thing to do.
Not only were there other options, perhaps better ones, perhaps much better ones, than invasions and occupations, not everyone was on board in the first place, nor should they be.
So, how does it work? If we agree we have the right to dissent in this nation,
what should have happened and was Bush wrong to try? No, he wasn't. He had enough support. More would have been better, but, he had enough to get congress's commitment to war. Bush's mistakes were his own.
Consider;
The 4th ID was supposed to come down from Turkey to act as the cap to Baghdad as 7th Marines and 3rd ID came up from the South. Turkey, at the last minute, refused us permission and 4th had to be moved, en masse, out of Turkey. Out of position, the plan blown up before it even started, we could have waited. Bush chose otherwise and we started the invasion. This lead directly to the chaos and looting and whatever goodies there was to move out of Baghdad flooding North and West. That had nothing to do with congress or the media. This was a HUGE mistake. This was red flag number one; A key regional ally had refused us.
When Baghdad was taken, US generals on the ground wanted and expected Iraqi military personnel to be pressed into service to help patrol and keep the peace. Instead, we disbanded their army and put 300,000 young men out of work. 300,000 young military men. This was not congress's or the media's mistake. Oopsie #2.
Members of the Ba'ath party ran everything in Iraq and were now out of power. We could have allowed the Iraqi people to decide who were the worst ones and let them deal with them and put the rest to work keeping things working. The administration chose to alienate all Ba'aths from the rebuilding of Iraq. Once all these people, especially the majority who were just doing a job, knew they had no future, the insurgency started within the next 72 hours. Was this congress or the media's idea? #3.
People like Al Sadr were allowed to set up little fiefdoms and assume local power, becoming extra governmental entities replete with their own agendas and motives. #4.
Add all of this together and, viola; instant insurgency.
All of this happened prior to 2006 when the GOP held both chambers and the WH. All of this happened when Don Rumsfeld was a rock star and the media ate him up like candy. All of this happened when Bush had it all.