" - Rachels, J pg92 (2003).
The Muslim terrorists could argue that by bombing the Atocha train station 200 people died, but as a result, a pacifist government has since been elected to power in Spain. This government has vowed to withdraw all 1000 troops stationed in Iraq and Afghanistan, and withdraw support for the American led War on Terror. For the Muslims, this could mean there are 1000 less troops to be killing their countrymen, less chance of their innocent civilians dying at the hands of the occupying forces (many have already been killed), and less countrymen made homeless by the allied force's air raids. .
The Muslims could also argue that it was better for the Spanish peoples greater good, as although 200 Spanish people have died, many more could have been killed if Spain had continued its unwavering support for the War on Terror, as 1000 troops abroad could have been increased to more in the future, and in the long term more than 200 Spanish soldiers may have lost their lives. .
People are only warranted in exercising power over another person for their own protection, according to John Stuart Mill in Rachels (2003). .
Using this theory, terrorists could argue that they exercised power (eg killed) over the Spanish people to protect Muslims from the western oppressors in the Muslim countries, as The Muslim terrorists feel they are being harmed by the western oppressors in their own country, and they see bombing western civilians as a possible way to end this oppression, so it is for the Muslim's own protection.
So using the main Utilitarian theory we could say that terrorists killed 200 people, but thousands more may have been saved, as the Spanish have withdrawn their troops, and it may have helped millions of Muslim people get a step closer to living in democratic nations free of western influence, or Basque people ruling themselves again. Either of these terrorists would argue the sadness caused by the deaths would be overwhelmed by the joy of democracies in these countries, so the attack was for the greater good.