More than a quarter of the Senate defied President Barack Obama on Thursday by introducing legislation that could raise sanctions on Iran, and compel the United States to support Israel if it launches a pre-emptive attack on the Iranian nuclear program.

The bill, sponsored by 13 Democrats and 13 Republicans, sets sanctions that would go into effect if Tehran violates the nuclear deal it reached with world powers last month or lets it expire without a long-term accord. The measures include a global boycott on Iranian oil exports within one year and the blacklisting of Iran’s mining, engineering and construction industries.

The goal, according to supporters, is to strengthen the negotiating leverage of the Obama administration as it seeks to pressure Iran into a comprehensive agreement next year that would eliminate the risk of the Islamic republic developing nuclear weapons. But it could also create added complications for U.S. negotiators, who promised Iran no new economic sanctions for the duration of the six-month interim pact that was finalized on Nov. 24 in Geneva.

“Current sanctions brought Iran to the negotiating table and a credible threat of future sanctions will require Iran to cooperate and act in good faith at the negotiating table,” said Sen. Bob Menendez, D-N.J., who spearheaded the effort with Sen. Mark Kirk, R-Ill.

Kirk called the draft law “an insurance policy to defend against Iranian deception.”

The Obama administration has furiously lobbied Congress not to impose new sanctions, even on a conditional basis, saying the increased economic pressure could force Iran to withdraw from the negotiating process and strain ties between the United States and its key negotiating partners — Britain, China, France, Germany and Russia. Washington is banking on these countries to persuade Tehran into accepting a final package that would ease trade, financial and oil restrictions if the country severely rolls back its uranium enrichment activity and other elements of its nuclear program.

Iran’s foreign minister also has said new sanctions could scuttle hopes of a diplomatic resolution. Iran maintains its program is solely for peaceful energy production and medical research purposes, but the United States and many other countries harbor severe doubts. Israel is perhaps most adamant in insisting Iran’s true intentions are to develop an atomic weapons arsenal.

A Senate vote won’t happen until January at the earliest and it’s unclear if the bill will have enough support. Majority Leader Harry Reid, D-Nev., has effectively blocked the issue from being addressed before legislators adjourn for 2013. Obama has yet to veto any legislation during his presidency, and his aides have refused to say if a sanctions bill that they see in violation of the spirit of the Geneva agreement would prompt such action.

Highlighting the opposition to new sanctions, Sens. Carl Levin, D-Mich., and Barbara Boxer, D-Calif., penned an opinion piece Thursday saying the package of restrictions “would run the risk of derailing efforts toward a peaceful resolution, and risk the unity we have achieved with the world community that has been so crucial.”

“We shouldn’t pass legislation now that would endanger negotiations that most people and countries want to succeed,” they said. “Such congressional action now could bolster the efforts of Iran’s militants to kill the deal.”

The agreement in Geneva gives Iran $7 billion in sanctions relief over the next half-year in exchange for it neutralizing its higher-enriched uranium stockpiles, not adding any new centrifuges and ceasing work at a heavy water reactor that potentially could produce plutonium used in nuclear weapons.

Under the Kirk-Menendez bill, the administration would have to certify to Congress every 30 days Iran’s adherence to the interim pact. Without that certification, the legislation would re-impose all sanctions that have been eased and put in place the new restrictions. Foreign companies and banks violating the bans would be barred from doing business in the United States.

Mark Dubowitz, a sanctions advocate at the Foundation for Defense of Democracies, said the new economic penalties could cost Tehran $55 billion annually in lost exports of petroleum, fuel oil and other industrial products.

“This should be incentive enough for Iran, if it is serious about saving its economy from a deep recession, not to cheat on its nuclear commitments and to move quickly to conclude a final deal,” he said.

Beyond the economic measures, the bill includes potentially contentious language requiring strong American action if Israel decides to launch a pre-emptive strike against Iran’s nuclear program. Israeli Prime Minister Benajmin Netanyahu has regularly issued such threats.

“If the government of Israel is compelled to take military action in legitimate self-defense against Iran’s nuclear weapon program, the United States government should stand with Israel,” the bill states. It calls for “diplomatic, military and economic support” to Israel in such an eventuality.

(AP)