In the 1950s and 60s one of the attacks on Democrats was that Democratic Presidents got America into wars. There was some justification for that charge. WWI, WWII, the Korean War, and the Vietnam War were all started under Democratic Presidents, and except for WWI, Democratic Presidents were supported in these wars by Democratic-controlled Congresses.
Well, this current war is a Republican War. A Republican President urged support for this war, and a Republican-controlled Congress went along with him. It was a Republican Secretary of State who went to the United Nations and told them that there was proof that Iraq was hiding weapons of mass destruction. It was a Republican Vice-President who claimed that our troops would be greeted as liberators.
The result? We have now lost more troops in the Iraq War than we lost civilians on September 11, 2001. ( Article here: http://news.yahoo.com/s/ap/20061226/ap_on_re_mi_ea/iraq ) Americans don't feel any safer, bin Laden is still at large, hundred of Iraqis are dying each month because of sectarian violence, and America's standing in the world has plummented. Meanwhile, the Taliban, who sheltered the evil organization that attacked us, is enjoying a resurgence in Afghanistan.
In the 2008 presidential election, the question will be whether the Republican Party nominee can escape political retribution for the horrible mistakes of the Bush Administration. This will be especially true if the GOP nominee is John McCain, who is now calling for more troops to go to Iraq. The only way that could happen would be if the Democratic Party nominee was a person who supported the war and if such a nominee was not able to articulate a foreign policy vision that would avoid such a disaster in the future.