During the peak of Madrid rush hour on the morning of March 11, 2004, ten explosions occurred aboard four commuter trains which killed 200 and injured around 2000. The main impacts of this operation were as follows:
1. It completely changed Spanish public opinion. The bombings immediately changed public support in favor of the opposing socialist party who opposed the war in Iraq with the leader of the socialist party, Zapatero, promising to withdraw all Spanish forces if his party won. This led to their victory in the elections and 1400 spanish troops were withdrawn from Iraq. Thus the attack toppled a hostile government which was allied with America.
2. The Honduras who were also a secondary enemy, fighting only because of being compelled by the Americans, after seeing the withdrawal of Spain from Iraq, hastened to retreat also.
3. The entire European-American alliance was shaken with a number of countries stating their departure or limiting the time they would stay on.
Thus this single deterrence operation led to the withdrawal and scaling down of many international forces and was considered one of the first real deterrence operation since the beginning of American aggression in the first Gulf war.