A non-partisan study by the Congressional Research Service (CRS) has determined that whatever the sanctions against Iran might have done, they have not hindered that nation's pursuit of a nuclear weapon.
In fact, the study indicates the sanctions "have not stopped Iran from building up its conventional military and missile capabilities, in large part with indigenous skills." This would probably come as a surprise to Joe Biden, who admits Iran may have fissile material but contends they have no missile to put it in.
Speaking of Biden, his defense of an isolated, sanction-based approach to Iran is a perfect example of the weakness of this administration's foreign policy.
During the VP debate, Biden bragged that the Ayatollah Khomeini "sees his economy being crippled [and] he sees the currency going in the tank." But Biden failed to see that this isn't hindering Iran's nuclear program one iota.
As the CRS study says, "Sanctions against Iran have not, to date, clearly reduced Iran's influence in the Middle East or its strategic capabilities in the Persian Gulf region."
Elliot Abrams, former adviser for President George W. Bush, put it thus: "The CRS conclusions demonstrate the error of Obama administration claims that their Iran policy is working."