Liberals do believe there are bad guys, but many lack the resolve to deal with these people.
Example, Clinton's dealing with Bin Laden, or lack there of. After FIVE!!!!! major terror attacks (1993 World Trade Center bombing, the 1995 bombing in Saudi Arabia, the 1996 Khobar Towers bombing in Saudi Arabia, the 1998 bombing of U.S. embassies in Africa and the 2000 bombing of the USS Cole) on US targets throughout the 90's and 2000, Clinton PROMISED to bring the killers to justice. These were empty promises.
Clinton didn't have the strength to do what needed to be done, which was putting boots on the ground in Afganistan. Because of his fear to go after the bad guys we had the 9/11 attacks. (Please don't try to put the blame for these attacks on the Bush administration-the attacks were planned by Bin Laden, in Afganistan from 1996 to 2001. That was Clinton's watch.)
Yes, war is awful. However, sometimes it is necessary. The majority of the American people know this and support the Iraq war and president Bush. In times when you have nuts flying planes into buildings, you may need to use force. We are at war with a violent group of lethal terrorists who have no regard for human life. You cannot look the other (ala Clinton) way in this war or we will die. You must face your enemy head on and destroy him. As barbaric as that may sound, unfortunately, it is true.