Reza Marashi is director of research at the National Iranian American Council.

As Barack Obama begins his second term as president, the United States faces a moment of truth in its slow-burning conflict with Iran. Fortunately, re-elected presidents have a unique mandate to pursue game-changing policies -- and Obama has a particular opportunity to reverse America's failing strategy toward Iran.

Obama has already taken important steps to put America back on the right track: He has walked the nation back from the brink of financial collapse, ended a disastrous war in Iraq, and set a deadline for ending the war in Afghanistan. America's healing process, however, has not occurred in a vacuum. From the impending austerity crisis to the ongoing civil war in Syria, the world's lone superpower still faces the herculean task of revitalizing its leadership abroad.

Perhaps no issue better illustrates the complex challenges that will define 2013 than U.S.-Iran relations. There are signs that Obama understands the stakes here: As he put it in his second inaugural address, "We will show the courage to try and resolve our differences with other nations peacefully -- not because we are naïve about the dangers we face, but because engagement can more durably lift suspicion and fear."

Iran is critical to solutions for no less than seven U.S. national security challenges: nuclear non-proliferation, energy security, Syria, Afghanistan, Iraq, counterterrorism, and Arab-Israeli peace. The status quo exacerbates each of these challenges: As U.S. Ambassador Jim Jeffrey -- a former Bush administration Deputy National Security Advisor -- candidly remarked: "If you want to be serious about regime change [in Iran], I give you Iraq 2003. Have a nice day."

And yet, despite Obama's stated preference for a peaceful solution to the U.S.-Iran conflict, we stand today at the precipice of a military conflict that policymakers and pundits almost unanimously agree would set off a chain of catastrophic events around the world.

How did a Nobel Peace prize-winning president see a long-standing conflict grow worse on his watch?..