As the Vietnam war directly affected more and more people (dead sons and acquaintences), it lost popularity at a grass roots level. People respond to how things impact them directly. It is why opposition to Iraq never took hold. The body count simply did not affect a large enough number of people.
As this economy affects more and more people, the backlash will be stronger and stronger. Eventually it will hit critical mass. Then it gets interesting.
I am a strong supporter of OIF, and defend GWB's Iraq policies fiercely whenever I hear anyone spouting moonbat talking points about it. Unfortunately, the White House didn't show the same amount of zeal in its defense. IMO, the treasonous 'Rat/DBM propaganda that was spread about Iraq eventually became accepted as fact by a majority of voters and was the biggest reason for the 2006 and 2008 electoral debacles.
The inability of the Bush Admin to adequately make the case for the Iraq war will no doubt be remembered by honest historians (if any exist) as one of its biggest failures.
Critical mass may be closer than we all think.