Some Trump-aligned Republicans like to argue that the Iraq War had as much support from Democrats as from Republicans. By that theory, George W. Bush was a proto-Democrat, and the war was another example of the failure of the entire elite, not just the GOP. Is that position justified?
No. Bush and Cheney pushed the war relentlessly on the political class. While it is true that some prominent Democrats voted for the war, it was not their idea, and they did so mostly out of fear of future retribution from the electorate. The only meaningful opposition to the war in its early stages came from the more principled elements of the left; what is now the populist right, including Trump, supported Bush enthusiastically until it became clear much later that the war was a mistake. The responsibility for the war consequently rests with Bush and the GOP, not the entire elite.