First let's take a look at the Democrats post Vietnam. I think there are 2 factors that led to the Democrat's woes after the war, one related to the war, one not so much and both were somewhat related to each other.
- The first was the emergence of the radical left - the hippies if you will. The radical left movement was certainly a result of the war but it scared the hell out of people and their association with the Democratic Party hurt the Democrats. The voters simply did not trust them to govern.
- The second was the Civil Rights Act. Do you really think the South went from blue to red because of the Vietnam war.
It was a case of a majority of the population seeing the image of America changing. The old morality and social order was dissolving before their eyes and they were afraid.
Now let's fast forward to the post Iraq war world. Lee Atwater and Richard Nixon's "silent majority" has become the very loud minority. The country has moved on when it comes to civil rights, women's rights, gay rights etc. So like the Democrats in the early 70s the Republicans no longer represent the majority of the American citizens. While the Vietnam war was responsible for the emergence of the radical left it was the election of a black Democratic president that was responsible for the emergence of the radical right - the Tea Party. Both were out of touch with the times.
Sorry Republicans, while the Iraq war was a mistake and mismanaged that's not your problem anymore than the Vietnam War was the Democrats real problem in the 70s.