I recently led a bipartisan congressional delegation to the Middle East and Europe to discuss regional security issues with key American partners . Beyond the strategic challenges posed by the Arab Spring lies an urgent threat -- Iran 's determination to achieve nuclear weapons capability . Iran 's effort , if successful , could destabilize the Middle East , spur a regional nuclear arms race and undermine America 's influence in this pivotal region . Unfortunately , the window to solve this problem without conflict gets smaller with each passing day as Iran attempts to master the enrichment of uranium . Several administrations have tried engaging Iran and offering security guarantees , but that has not prevented the country from pursuing the bomb or patronizing the world 's most dangerous terrorist groups . Economic and diplomatic pressures have n't worked either , but they have been episodic , gradual and largely unilateral . While the U.S. left Iran 's market years ago , we can still exert great pressure through financial sanctions , and President Barack Obama should do so . Our partners in Europe , Asia and the Middle East can and should do more to amplify the effect of U.S. sanctions if they are serious about stopping Iran 's nuclear proliferation . Some influential countries , however , may be unwilling to pay the costs associated with greater multilateral sanctions , either because they do not feel threatened by a nuclear-armed Iran or they see utility in having the U.S. being consumed with that threat . In the weeks ahead , it will be actions , not words , that demonstrate which countries are truly committed to stopping Iran . The latest round of European sanctions is designed to compel Iran to come back to the negotiating table . If the Iranians do so , the desire for a deal at any cost should not be permitted to overshadow our long experience in negotiating with rogue states . We must focus on the results rather than the process of negotiations . With its nuclear centrifuges continuing to spin , Iran can not be allowed -- as it has been in the past -- to further delay this process . Mere promises can not be rewarded with a loosening of pressure . Iran 's leaders must feel dramatic pressure that imperils their very hold on power until their abandonment of nuclear program can be verified . It is possible that only a strategy that jeopardizes the hard-line clerics ' hold on power in Tehran will give the Iranian regime sufficient reason to abandon its nuclear ambitions . Frankly , the Obama administration missed an opportunity to stand with Iran 's dissidents when they rose up against their oppressive rulers after the rigged elections in 2009 . It is hard to believe a less ideological government would be as intransigent as the current regime . Perhaps further sanctions could breathe new life into the budding democratic movement that for a brief moment brought a glimmer of hope to the Iranian people . In addition to sanctions , we must actively combat Iran 's influence throughout the Middle East . Our partners are perplexed at what they perceive as our lackadaisical response to Iran 's support of extremist proxies . And in Iraq , our partners believe that America 's abandonment of that country has left a vacuum that Iran is only too eager to fill . It is hard to see why the Obama administration has not expended more effort in trying to keep Iraq -- a potentially rich and influential country at the heart of the Middle East that was liberated at such great cost -- more firmly in the American camp . Finally , there is the low-hanging fruit of Syria . Bashar al-Assad 's regime may be Iran 's most important strategic partner . Instead of aggressively combating Syria 's support to Hamas and Hezballah and interference in Lebanon and Iraq , the Obama administration came to office seeking to engage al-Assad . It failed . Now the president has finally acknowledged that it 's time for al-Assad to go . America should not defer to obstinate Russian diplomats at the United Nations about Syria . Instead , we should lead an international effort to apply tremendous pressure on Syria and provide demonstrable support to its growing political opposition . The longer the Syrian crackdown is allowed to continue , the greater the risk of chaos and the harder it will be to put Syria back together . If Syria goes down , it would be a serious blow to the Iranian regime . There is no substitute for American leadership in the Middle East . It is time for the Obama administration to show it . Without recourse to war , these steps represent the best hope of confronting the challenges posed by Iran 's nuclear proliferation and patronage of terrorism . If these measures ultimately fail , the international community may be forced to confront the difficult decision of using military force in face of an implacable Iran . Follow CNN Opinion on Twitter . Join the conversation on Facebook .
Eric Cantor : Iran 's determination for nuclear weapons proliferation is an urgent threat . Bush : We can exert stronger pressure on Iran through financial sanctions . He says we must combat Iranian influence throughout the Middle East . There 's no need for American intervention in this critical region , he says .