Washington D.C. - United States President Barack Obama warned on Wednesday that the only alternative to the nuclear agreement with Iran was war in the Middle East.

“The choice we face is between diplomacy and some form of war – which might not happen tomorrow, but will happen soon,” the president said during an address to the nation at the American University in Washington.

“Military action will be far less effective than an agreement in preventing Iran from getting nuclear weapons,” the president stated, adding that even Israeli analysts agreed that a military strike would only retard Iran’s nuclear program by a few years.

“This deal has to be judged by what it achieves in preventing Iran from obtaining a nuclear weapon,” Obama said, describing it as “the most comprehensive anti-proliferation regime” ever.

Wednesday’s address was an attempt by the president to mobilize public support for what is expected to be a bruising battle in Congress over approval of the agreement. He appealed to the public to pressure their representatives into supporting the agreement, saying that “if Congress kills this deal we will lose America's credibility in international diplomacy.”

Though the prime audience of the speech was the American public, the president made several references to Israel and Prime Minister Benjamin Netanyahu, one of the agreement’s key opponents.

“I don't doubt Netanyahu's sincerity but I think he is wrong,” the president said, noting that “with the exception of Israel, every country supports the agreement,” as do the United Nations Security Council and other international agencies.

“To the Israeli people I say this: Nuclear-armed Iran is more dangerous than an Iran that benefits from sanction relief,” the president stated. He added that he was “ready to discuss upgrading Israeli defense capabilities.

Jerusalem dismissed President Barak Obama’s Iran speech on Wednesday night. “Israel does not doubt President Obama’s sincerity, but we disagree with his position,” said a senior Israeli official.

“This agreement does not prevent war but brings it closer, because it gives Iran international legitimacy to build an infrastructure and manufacture an arsenal of nuclear weapons,” the official said. “It also funds its aggressive terror machine with hundreds of billions of dollars.”

Iran’s current economic distress limits the development of such destructive capabilities, the official said, but “the removal of sanctions will propel such development to a degree that it imperils Israel, the region and the entire world.”

Rather than blocking Iran’s path to nuclear weapons, the agreement does the opposite,” the official said. “It enables Iran to proceed along parallel tracks to a bomb, whether it keeps to the agreement or not. President Obama was right in saying that an Iran with nuclear weapons is far more dangerous than an Iran that benefits from sanctions relief, but the agreement gives Iran both the ability to develop nuclear weapons and hundreds of billions of dollars to sponsor increased terrorism.”

Addressing the argument of opponents of the agreement that a better deal was possible, Obama said that they were right. “Walk away and you will get a better deal – for Iran.”

He compared the opponents of the agreement to those who had been most vocal in pushing the U.S. into war with Iraq in 2003. “If we have learned anything, it is that wars are not painless,” the president said. “The only certainty in war is human suffering.”

He called on Americans to “resist the drumbeat of war” and to “think less about being strong and more about being right.”

The speech came at a time when the public dispute between supporters and opponents of the agreement is heating up in Washington, with Netanyahu and several American Jewish organizations providing vocal and logistical support for Republican opponents of the deal in Congress.

Obama and Netanyahu are both struggling for the support of a group of Democratic senators and congressmen who have not yet decided which way they will vote on the agreement.

American lawmakers are due to hold a no-confidence vote on the agreement before September 17, which will include voting whether or not to lift Congressional sanctions on Iran.

The two leaders are also fighting for the heart of the Jewish community in the U.S. On Tuesday, Netanyahu called on the community to publicly oppose the agreement, whatever their individual political affiliations.

Obama, for his part, told Jewish leaders he met with at the White House on Tuesday that an all-out fight against the agreement could lead to split in the community and a crisis in U.S.-Israel relations.

Obama’s remarks were delivered at the American University in Washington, the scene 52 years ago of a speech by President John Kennedy in which he argued in favor of diplomacy to avoid a nuclear confrontation with the Soviet Union.

Opposition leader and Zionist Union chairman Isaac Herzog responded to Obama's speech, tweeting that "Netanyahu mustn't get into frontal and personal conflict with President Obama. On the contrary, he must walk into the Oval Office, argue with him and say harsh things about the deal with Iran, but above all he has to hold a dialogue with him over the way to build a wide global and regional front facing Iran.

"A public confrontation between Netanyahu and Obama gladdens our enemies and foes, who enjoy seeing us quarrel for the whole world to see."