They did, after their farce of an election. Obama showed him where he stood.....far away from them. Horribly botched opportunity.
Much more can be done, such as banning insurance for shipments to Iran, banning all military sales to Iran, ending all trade credits, banning all financial dealings with Iranian banks, limiting Iran's access to international capital markets and banking services, closing air space and waters to Iran's national air and shipping lines, and, especially, ending Iran's ability to import refined petroleum. These would be truly "crippling" sanctions. They would work if implemented.
They would be crippling and may work, but it wouldn't occur without repercussions. Allowing Iran to develop a nuclear weapon is unthinkable. However, taking necessary action to stop it will not cause the regime to just pack it up and go away. I know she's not that naive.