Prior to 9/11, many were complaining that the U.S. did not retaliate in any sufficient manner to terrorism. It was stated over and over. Please correct me if I am wrong:

April 1983 U.S. embassy in Beirut bombed, killing 63.
October 83 U.S. Marine barracks in Beirut bombed, killing 241.
December 83 U.S. embassy in Kuwait bombed, killing 6.
January 84 Malcolm Kerr, president of the American University of Beirut, assassinated.
April 84 Hezbollah attacks the environs of a U.S. airbase in Spain, killing 18 servicemen.
September 8: U.S. embassy in Beirut again bombed, killing 16.
December 84 Two Americans murdered on a hijacked plane in Tehran.
June 85 U.S. seaman killed on a hijacked plane in Beirut.
World Trade Center bombing of February 93
2 attacks on U.S. soldiers in Saudi Arabia in 95 and 96
2 U.S. embassies blown up in East Africa in August 98
USS Cole bombed in Yemen in October 2000

Nearly 600 Americans lost their lives to due to terrorisim before 9/11.

All of these were highly publicized incidents, yet the U.S. government neither attacked the enemy nor changed policies.