"This seems to say that if Clinton had responded to the USS Cole, then Al-Qaeda might not have brought down the World Trade Center towers."
Clinton couldn't respond to the Cole bombing. At the time he was trolling for $$ for his trailer trash monument library in Little Rock and the only funders he could find were fronts for terrorist groups!!
Also, declaring war on Al-Qaeda would have hurt Clinton's chances for a Nobel Peace Prize. By focusing on his "legacy", he made sure he didn't have one. Clinton was only willing to go to war for Muslims against Christians, not the other way around.