Behind closed doors, the Iranian regime probably cannot conceal its surprise and delight at what it has gotten away with. For more than 10 years, Iran has succeeded in deceiving foreign governments, thwarting nuclear inspectors and keeping sanctions weak and feckless. During that time, Iran has not broken stride in expanding its nuclear program, and it has now announced plans for 10 new enrichment facilities.

Iran's greatest feat has been its success in lulling global leaders — including many in the U.S. administration and Congress — into complacency, based on the belief that the threat posed by Iran's nuclear weapons program can be negotiated away through engagement and concessions by the West. This approach also largely ignores the totality of Iran's multifaceted threat.

The range and accuracy of Iran's ballistic missiles continue to improve, with U.S. forces and allies in the Middle East and Europe now within striking distance. Iran is also quickly accumulating an array of advanced conventional weapons in its effort to dominate the Persian Gulf and the world's oil supply.

Last month, the International Atomic Energy Agency made the startling revelation that Iranian scientists may have tested advanced components of nuclear warheads. Nuclear experts note that such technology, once mastered, would allow for the production of smaller and simpler nuclear bombs, and would make it easier for Iran to put a nuclear warhead on a missile.

The IAEA also issued a report last month saying that yet another camouflaged nuclear facility, this time at the recently disclosed Qom site, was at "an advanced state of construction." With additional installations widely suspected, who knows what will be uncovered next?

The IAEA should immediately cease all technical assistance to Iran and should suspend Iran's membership privileges in the organization. Until such actions are taken, the U.S. should not send one more penny of taxpayer funds to the IAEA that benefit Iran's nuclear program.

The regime in Iran knows only hardball, and nothing less than overwhelming and crippling sanctions could produce a reversal of its threatening programs and policies.

That is why the United States must be prepared to act alone, if necessary, and with every weapon in its political and economic arsenal. The Iran Refined Petroleum Sanctions Act is one such tool. It targets one of Iran's major weaknesses — namely, its dependency on foreign gasoline and other refined petroleum products. By placing financial sanctions on U.S. and foreign companies providing these crucial resources, Iran's economic lifeline would be severed and its already weak economy would crumble.

But these sanctions must be coupled with action on all fronts. The U.S. must also specifically reject Iran's claim to an inalienable right to produce nuclear fuel. We must strengthen existing laws to prevent the transfer of prohibited materials and technology to Iran. Responsible nations should impose a ban on travel by senior Iranian regime officials and their families to Europe and the U.S. We should strengthen bilateral and multilateral efforts to shut down accounts of those doing business with the Iranian Revolutionary Guard Corps or its affiliated entities; deny Iran access to euros and U.S. dollars; and freeze the assets of those who violate U.N. sanctions on Iran. Concurrently, we should offer our full support to the Iranian people and increase funding for Iran democracy programs.

The weakness of recent actions has been daunting. The IAEA mustered only a weak censure of Iran; the U.N. Security Council has said that it was disappointed; the White House has maintained its wait-and-see approach; and the Iran Refined Petroleum Sanctions Act continues to languish because many remain true believers in the mirage of engagement. However, the threat is immediate, and the time to act has arrived.