President Obama warned that if Congress blocks the Iran nuclear deal next month, it would result in "some form of war."

"Let's not mince words. The choice we face is ultimately between diplomacy or some form of war," he said during a major foreign policy address in Washington today. "Maybe not tomorrow, maybe not three months from now, but soon."

Obama took a page out of John F. Kennedy’s foreign policy playbook, drawing parallels between the Obama doctrine and Kennedy’s Cold War stance towards the former Soviet Union in his continuing effort to sell the Iran nuclear agreement to a skeptical Congress and American public.

“The prospect of nuclear war was all too real,” Obama said of the state of world affairs in 1963. “But the young president [Kennedy] offered a different vision. Strength, in his view, included powerful armed forces and a willingness to stand up for our values around the world.”

During his remarks at American University -- the very same setting for a major Kennedy foreign policy speech in 1963 -- Obama admitted that “not every conflict was averted” during the Cold War but he stressed that “the world avoided nuclear catastrophe” by creating the time and the space to defeat the Soviets through diplomacy.

“The agreement now reached between the international community and the Islamic Republic of Iran builds on this tradition of strong principled diplomacy,” Obama said. "We have achieved a detailed arrangement that permanently prohibits Iran from obtaining a nuclear weapon. It cuts off all of Iran's pathways to a bomb."

The agreement is expected to face a vote in mid-September after the congressional summer recess.

Obama also stressed his belief that the Iran nuclear deal is “the most consequential foreign policy debate that our country has had since the invasion of Iraq” in 2003, challenging some lawmakers who supported the effort to oust Saddam Hussein but have been critical of the pact that aims to prevent Tehran from obtaining a nuclear weapon.

So far, the president has met personally with over 80 Members of Congress while senior administration officials have lobbied more than 175 lawmakers to discuss the deal, according to an administration official.

“Between now and the congressional vote in September, you are going to hear a lot of arguments against this deal, backed by tens of millions of dollars in advertising,” Obama predicted. “And if the rhetoric in these ads and the accompanying commentary sounds familiar, it should -- for many of the same people who argued for the war in Iraq are now making the case against the Iran nuclear deal.”

In order to block the deal from being implemented, Republicans must build bipartisan support majorities in the House and Senate to overcome presidential vetoes.