With the discussion about sanctions against Iran it is good to remember how ineffective sanctions usually are. Yet proponents of sanctions keep asking for more - claiming effectiveness that on closer look doesn't hold. In fact moral arguments work much better than blackmail.
Stratfor recently even claimed that the Apartheid had been beaten by sanctions. In fact there were sanctions for many years against South Africa - without much effect. The advocates of sanctions knew that but it didn't bother them as their real goal was to further discussion on the moral basis of apartheid. The South African regime defended Apartheid with the argument of "separated development". In a world where many white parents would be deeply shocked when the children would marry blacks such an argument certainly had its appeal. By shifting the discussion to the way this "separate development" reserved the best jobs and best lands for the white people the apartheid adversaries succeeded in making apartheid look bad morally. That did the job.
A similar argument can be seen in the demise of communism. The Macchiavellians like to claim that the fomenting of war in Afghanistan in 1979 by Carter and Brzezinski and the the start of a new arms race that the Soviet Union couldn't keep up with did the job. But Gorbachev has said that it was the detente that had convinced him that the West wasn't as bad as communist propaganda preached. Reagan's moral appeals ("mr. Gorbachev, tear does this wall" and calling the Soviet Union "the Evil Empire") did the rest.
In Milosevic's Serbia and Saddam's Iraq sanctions enriched a clique closely connected to the ruler. They strengthened rather than weakened his control over the country. Milosevic was in the end brought down with a "color revolution" - a foreign sponsored semi-coup. And Saddam was brought down with force.
Given this background one would expect stronger support for a moral approach. Yet the Macchiavellians manage to keep monopolizing the discussion when it comes to disagreeable regimes like Iran, Zimbabwe, North Korea, Birma, etc. In my opinion a moral approach would be much more fruitful. Unfortunately Obama seems incapable to shed the shadow of the immoral Cheney.