The plan is designed to curtail the financial freedom of every Iranian official, individual and entity the Bush administration considers connected not only to nuclear enrichment efforts but to terrorism, government corruption, suppression of religious or democratic freedom and violence in Iraq, Lebanon, Israel and the Palestinian territories. It would restrict the Tehran government's access to foreign currency and global markets, shut its overseas accounts and freeze assets held in Europe and Asia.
[...]
U.S. intelligence agencies have spent months trolling through the personal accounts of Iranian leaders in foreign banks, analyzing Iranian financial systems and transactions and assessing how the government does its banking. They have calculated the amount of foreign investment at stake and even which charities have connections to the Tehran government.

Decades of stand-alone U.S. sanctions on Iran, North Korea and Cuba have failed to bring down those country's leaders or modify their behavior. But U.S. officials believe that if other Western allies join in a sanctions pact, it could magnify pressure on Iran in much the same way that some Bush administration officials believe U.N. sanctions helped persuade Libya to give up its nuclear weapons program in 2003.

With Britain, France, Germany, Italy and Japan on board, collective sanctions would "isolate the Iranian regime," and see it "shunned by the international financial community," according to one internal Bush administration memo.
[...]
The potential side effects have led European officials to turn the pressure back on Washington to hold direct talks with Iran.

"The sanctions could make Iran miserable, and Iran can respond by making everyone miserable back," said one senior Western official, who consulted on the issue recently with Rice. "In the end, the whole world is miserable and Iran gets to keep its nuclear program." [...]

nah, i don't see this ending so peacefully.