US President Barack Obama made a vigorous case for the nuclear deal with Iran on Wednesday, warning lawmakers that rejecting diplomacy would lead to war and destroy the western superpower's credibility.
Casting the debate over the agreement with Tehran as "the most consequential foreign policy debate" in a decade, Obama said Congress must not waver under pressure from critics whom he said history had already proven wrong.
"Many of the same people who argued for the war in Iraq are now making the case against the Iran nuclear deal," he said, urging lawmakers to instead choose an American tradition of strong diplomacy.
"Congressional rejection of this deal leaves any US administration that is absolutely committed to preventing Iran from getting a nuclear weapon with one option: another war in the Middle East."
"If Congress kills this deal, we will lose more than just constraints on Iran's nuclear program or the sanctions we have painstakingly built," he warned.
"We will have lost something more precious. America's credibility as a leader of diplomacy. America's credibility as the anchor of the international system."
Positing the now unpopular Iraq war as a cautionary tale, Obama recalled president John F. Kennedy's diplomatic efforts to engage a nuclear Soviet Union as a more worthy example to follow.
Obama's remarks came at the American University, in Washington, where in 1963 Kennedy used a commencement address to argue vehemently for peace with the Soviet Union in the face of panic over a nuclear conflagration.
Speaking a year after the Cuban missile crisis, Kennedy cautioned against brandishing US power to bring about a the "peace of the grave or the security of the slave."
Instead, he announced diplomatic efforts to check "one of the greatest hazards which man faces in 1963, the further spread of nuclear arms."
"The young president offered a different vision," Obama said. "Strength, in his view, included powerful armed forces and a willingness to stand up for our values around the world."
Obama's diplomatic deal would give Iran sanctions relief in exchange for curbs on its nuclear program, which Washington long believed was cover for building a bomb.
War and peace
Congress is expected to vote on the issue within weeks.
Critics have angrily denounced Obama's rhetoric and what they say is a false dichotomy between war and peace.
The alternative to a bad deal, they say, is a better deal that not just subjects Iran to inspections and limits enrichment, but dismantles the nuclear program altogether.
The debate has split Congress largely -- although not exclusively -- along party lines, with Republicans, who are in the majority, staunchly against the accord.
Obama will need to win the support of fellow Democrats in order to avoid having the deal struck down by lawmakers.
Here, history has proved as much a burden as an aid to Obama.
The United States and Iran severed ties following the 1979 Islamic Revolution, which saw 52 American embassy staff and citizens held hostage for 444 days.
Iran's antagonism toward the United States, Israel and support for terror groups in the Middle East since then has given many lawmakers pause, with a number of Democrats already breaking ranks.
Obama admitted that Iran might use cash coming its way under sanctions relief to fund "terrorist organizations."
But he said that was preferable to Iran -- which he described as "dangerous and repressive" -- armed with a nuke.
Obama singled out Israel as an opponent of the deal, but said it would also benefit from an Iran blocked from gaining nuclear weapons.
"Every nation in the world that has commented publicly -- with the exception of the Israeli government -- has expressed support," he said.
"No one can blame Israelis for having a deep skepticism about any deals with a government like Iran's."
But, he added "a nuclear armed Iran is far more dangerous to Israel, to America, and to the world than an Iran that benefits from sanctions."