In 2005, Congressman Rob Andrews (D-NJ) and I cofounded the Iran Working Group in the House of Representatives to study the coming threat from Iran and make policy recommendations to Congress and the administration. Behind closed doors in Washington, two options emerged as endgame scenarios for Iran's nuclear program: pursue ineffective sanctions waiting for an Israeli military strike or defer to the United Nations and an eventual Iranian bomb. We knew this was a false choice. Unlike the 1981 strike on Iraq's Osirak nuclear reactor, an Israeli strike against Iran would be complex, unpredictable and not a long-term solution. With many targets scattered around the country (some buried deep underground), an air strike would delay Iran's nuclear activities but would not permanently eliminate the threat. At the same time, conceding nuclear weapons to the Iranian Revolutionary Guard Corps with only a policy of containment would set off an arms race in the world's most unstable region. After an Iranian bomb comes a Saudi bomb followed by an Egyptian bomb - making the world unsafe for our children. As a state sponsor of terror with a proven track record of transferring advanced weapons to Hizbullah, a nuclear-armed Iran poses a threat to the future of the US and Europe - not to mention the existential threat to our democratic ally Israel. TO STOP the emergence of a nuclear Iran and avoid military conflict, Congressman Andrews and I conducted a comprehensive analysis, searching for vulnerabilities in Iran's economy. With the help of the Congressional Research Service, we discovered a critical Iranian weakness. Despite its status as a leading oil exporter, Iran so mishandled its domestic energy supply that the regime relied on foreign sources of gasoline for 40 percent of its supply. A restriction of gasoline deliveries to Iran administered though multilateral sanctions and enforced by the world's most powerful navies would pit the Western democracy's greatest strength against Iran's greatest weakness - all without a shot being fired. In 2005 and again in 2006, we introduced congressional resolutions calling for a multilateral restriction of gasoline deliveries to Iran as the most effective economic sanction to bring Iran's leaders into compliance with their commitments under the Nuclear Non-Proliferation Treaty. In 2007, we introduced the Iran Sanctions Enhancement Act to expand existing US sanctions to the provision of gasoline to Iran - including suppliers, brokers, shippers and insurers. This April, Congressman Brad Sherman (D-Calif.) and I reintroduced this bipartisan legislation. Following our bills, Iran imposed an unpopular gasoline rationing scheme, showing it was worried. Last year, candidates Barack Obama and John McCain both endorsed the gasoline restriction, and this year, House and Senate leaders reintroduced the gasoline sanctions bill as the Iran Refined Petroleum Sanctions Act, now headed by Congressman Berman and our coalition of 343 congressmen and 76 senators behind the bill. After four years and six months, Congress will finally consider our gasoline restriction legislation this week. While this bill could emerge as the key tool to peacefully end our standoff with Iran, it will prove meaningless if the president keeps gasoline sanctions locked in his diplomatic toolbox. Our Petroleum Sanctions Act would add a ban on the provision of gasoline to Iran under the old 1996 Iran Sanctions Act, a law that already makes it illegal to invest more than $20 million in Iran's oil and gas sectors. Under this old law, our president must declare someone in violation before sanctions take effect. Few realize that no American president has ever enforced this provision. According to the Congressional Research Service, at least 20 companies are currently violating the 1996 law. For the threat of sanctions to change Iran's decision-making, Iranian leaders must believe an effective gasoline sanction is credible. If President Obama, like his predecessor, lacks the will to enforce the 1996 Sanctions Act, we should not expect Iranian leaders to believe a new threat of additional sanctions. In October, Congressman Ron Klein (D-Fla.) and I authored a bipartisan letter to the president urging him to enforce the Iran Sanctions Act and demonstrate to Iranian leaders the credible potential for a restriction of their gasoline. Fifty Democrats and Republicans signed our bipartisan letter. When asked why the administration failed to enforce the 1996 law, Assistant Secretary of State Jeffrey Feltman promised a 45-day review for the State Department to determine whether it would pursue sanctions against current lawbreakers. Secretary Feltman's clock ran out this weekend. For the House's new 2009 Iran Refined Petroleum Sanctions Act to succeed, the Iranians must believe the president will enforce it. Otherwise, we will continue down a failed path of diplomacy in the absence of effective sanctions. As the architect of this legislation, I hope the House and Senate will pass our Iran gasoline sanctions bill into law. As an American, I hope the president will enforce it. The writer represents Illinois' 10th Congressional District and authored numerous bipartisan sanctions provisions on Iran that won congressional approval.