Excerpts from Books and Wikipedia
"A series of explosions brought horror to the Spanish capital. . . . The bombers struck during rush hour to maximize the death toll. . . . The Spanish government was a strong ally of the United States and its invasion of Iraq, making Islamic fundamentalism a more plausible explanation. . . . In the general elections held three days after the explosions, the ruling People's Party was unexpectedly beaten, and the new Socialist Prime Minister, Jose Luis Rodriquez Zapatero, immediately confirmed his election promise to withdraw Spanish troops from Iraq." [Furtado: 1001 Days]