Clinton should have done more after the 1993 WTC bombing and the 1998 embassy bombings. All he did was shoot a few missiles into some empty desert. However, Republicans are equally to blame here. They were busy salivating over the Lewinsky scandal and claimed that
Operation Infinite Reach (among several other US military campaigns) was merely an attempt to distract the public. Also, the USS Cole bombing should have been an indication to Bush that Clinton had not neutralized the terrorist threat posed by al-Qaida. However, people were once again caught up in a sex scandal in 2000 about some pregnant guy named Chad and didn't have enough room in their brains to care about potential threats to national security.
All-in-all, Clinton, Bush, and their respective political parties are all equally to blame for 9/11 and anyone who contends differently is showing an obvious bias and an unwillingness to acknowledge that their chosen favorite is flawed.