James F. Jeffrey is the Philip Solondz distinguished fellow at The Washington Institute for Near East Policy. He served as U.S. ambassador to Turkey from 2008 to 2010 and Iraq from 2010 to 2012.

President Obama speaks this month about the nuclear deal with Iran. (AP/Carolyn Kaster)

The drama is breathtaking. A decisive president makes a crucial decision on the Middle East issue that defines his tenure, a decision that could transform not just the specific situation but regional security. Yet he has just lost both houses of Congress, opinion polls on the decision are heading south, lawmakers are up in arms, and even some in his administration have doubts. But rather than hesitate, he drives ahead.

Barack Obama, 2015, with Iran? No, George W. Bush, 2006-07, with the Iraq troop surge to save his effort in the country he ordered the U.S. military to invade. Both presidents, at the same point in their tenures, pushed major initiatives against very strong domestic opposition. Given the similarities, the fate of Bush’s surge could provide insight into the fate of the Joint Comprehensive Program of Action with Iran.

Bush’s success suggests that, one way or another, Obama will also prevail in implementing the Iran deal. He either will beat back a congressional attempt to strip him of sanctions power, or if not, likely will secure enough Hill votes to sustain a veto. But his options do not end there. Presidents as commanders in chief have enormous power when dealing with national security issues, if — as Obama and Bush both do and did — they deeply believe in what they are doing. Even if Congress strips him of the power to lift sanctions, the president could dither on implementing them, or deploy his authority in what he keeps asserting is a “war or peace” situation to ignore Congress. Finally, he could cut a side deal to trade limited American noncompliance with the deal (i.e., some U.S. sanctions remain) for commensurate Iranian noncompliance, for example on verification terms, centrifuge numbers or stockpile limits.

But aside from presidential grit and creative legal reasoning, there is another reason that Obama is likely to prevail. The international system over which the United States still presides rests on the ability of the American president to act unilaterally even on unpopular decisions if a vital national interest is at stake. Bush, facing the collapse of his Iraq policy if he could not curb that country’s descent into civil war, acted on such an interest, despite resistance in Congress, deep skepticism in the Iraq Study Group and doubts among many top advisers.

We see similar behavior by Obama on Iran. His American University defense of the deal was simplistic, but left no doubt where he stands. That doesn’t mean the agreement deserves to survive, only that Obama will use every trick in the book to ensure it does. Just as Bush coupled the surge with commitments for a relatively rapid withdrawal of U.S. forces from Iraq, Obama might have to concede points on his Iran project to critics to save the deal, but save it he likely will.

Which means the more interesting question is not whether the deal will survive, but whether the nuclear agreement and Obama’s underlying Iran project will suffer the same fate as seen with Bush’s Iraq project.

Like the surge, the deal has become the defining element in a presidential project to transform the Middle East. Obama’s is focused on Iran, while Bush’s focused on Iraq. The first characteristic of these projects is serious risk — with Iraq, major conflict; with Iran, regional and alliance turbulence. The second is deviation from standard U.S. foreign policy since 1945. With few disastrous exceptions (North Korea 1950, Bay of Pigs 1961), that policy has concentrated on defending its global perimeter while containing first communism and, since 1989, chaos in places like the Middle East, in part due to public opposition to more ambitious but riskier national gambits.

But ambitious is exactly what the projects behind the surge and Iran deal have been — to transform, respectively, Iraq and Iran, and thereby move the Middle East decisively toward a peaceful global community. Bush and Obama’s means differ, but not the goal: fix the problem rather than, as usual, manage it.

That goal is easy to document with Bush. As he said in his 2005 inaugural address, “The best hope for peace in our world is the expansion of freedom in all the world.” He clearly, as Bob Woodward reports in “Plan of Attack,” saw transforming Iraq into a democratic ally as central to sparking wholesale democratic change in the region. Obama is more coy, but, from his 2009 letter to Supreme Leader Ali Khamenei to his administration’s constant hints that the trust generated by the deal with Iran can “flip” a longtime foe into a responsible, status quo stakeholder, the same goal can be discerned.

So the fate of Bush’s project can shed light on Obama’s. While the surge worked militarily, and some American-encouraged democratic reforms survive, the United States did not succeed in the larger project to inculcate our values in Iraq, and even less in the region as a whole. There are many reasons for the “Arab Spring,” but Iraq was not among them. The surge was a courageous gamble by Bush that saved the United States and Iraq from military defeat, but has not transformed the Middle East.

Obama’s Iran project faces similar risks. Ambitious efforts of this kind require projecting our values onto very different societies, with extremely broad goals based on the presumed universality of those values. But this is a huge lift with little precedent aside from America’s unique experiences in Japan and Germany. And thanks to the timing of U.S. elections, in both cases, soon after tactical success — implementing the surge, negotiating the Iran deal — the president in question had or has to make way for a successor, although in both cases, the larger project still faced or faces public skepticism.

Bush’s successor, Obama, campaigned on an “ending America’s wars” theme not compatible with a transformational Iraq policy, as seen in his half-hearted effort to keep a troop presence there. Likewise, Obama will yield office almost certainly to someone more skeptical toward Iran. That includes any Republican, but also Hillary Clinton, his former secretary of state, who said last month that “even if we do get such a deal, we will still have major problems from Iran.”

Thus, even if Obama is right on Iran’s potential transformation, he won’t be around to nudge it forward, just as Bush was not there to ensure that the surge’s success could jump-start regional change. It’s not that Bush had to be proven wrong on Iraq; rather, absent immediate, demonstrable and extraordinary success, the political friction such a bold endeavor generated almost guaranteed he would be succeeded by a leader who isn’t enthused about carrying it forward. The timing didn’t work for him, and well might not for Obama. His bet on an Iran transformed has to be immediately, demonstrably and extraordinarily right, or his larger project could suffer the same fate as Bush’s in the hands of his successor.