The AUMF was not an authorization for the invasion of Iraq. The separate "Iraq Resolution" was largely passed by Republicans.

House:

Republican	yay 215, nay 6, no vote 2;
Democratic	yay 82,  nay 126, no vote 1;
Independent	 yay 0, nay 1, no vote 0.

Senate:

Republican	yay 48, nay 1;
Democratic	yay 29, nay 21;
Independent	 yay 0, nay 1.

However, I must admit that after the AUMF passed I was fatalistic about the US going to war in Iraq.