The whole westward expansion, moving Native Americans off their lands, could be justified in the name of the greatest good for the greatest number. Many more people could live in an area with cities and factories than could support themselves off the land in the traditional way. We now have hundreds of millions of people in America.
Prior to the Civil War, arguments for slavery included the effect on the economy, how many farmers in the south would be unable to make a living, how the entire U.S. economy depended on slave labor.
Think this is all just history? Listen to some arguments today that we need to violate the constitutional rights of people who might be terrorists, or torture people who support our political enemies because
"It will save potentially thousands of American lives."
Look at the number of people who choose not to think about the working conditions under which the cheap goods they buy at Wal-Mart are made.
"Just think of the American jobs that will be lost. Think of how much more everything would cost if it we insisted that people in Nicaragua making our clothes had to have safe, clean working conditions and only work less than ten hours a day and be paid more than pennies an hour."
Utilitarian thinking is alive and well.