President Obama took a quick trip across D.C. Wednesday to sell his Iran nuclear deal in a speech at American University regarding what he called “the most consequential foreign-policy debate that our country has had since the invasion of Iraq.”

Here are nine of the most striking lines from his pitch:

1. “Congressional rejection of this deal leaves any U.S. administration that is absolutely committed to preventing Iran from getting a nuclear weapon with one option: Another war in the Middle East.”

Obama warned that the choice is “ultimately between diplomacy or some form of war,” arguing that if the accord dissolves, Iran will have an accelerated ability to build a bomb.

2. “The critics are right: Walk away from this agreement and you will get a better deal—for Iran.”

Obama argued those who contend that the U.S. could reject the deal and still maintain sanctions are “selling a fantasy.”

>>> 8 Things Obama Got Wrong on the Iran Deal

He said rejection would instead lead to the unraveling of multilateral sanctions, giving Iran economic relief.

3. “Nuclear material isn’t something you hide in the closet.”

Obama addressed concerns that international inspectors would have to give Iran 24-hour notice prior to access nuclear sites. He said for Iran to cheat, it would need a “secret source” for every aspect of its program—something he said no nation has ever been able to “pull off.”

4. “Just because Iranian hardliners chant ‘Death to America’ does not mean that that’s what all Iranians believe. … It’s those hardliners chanting ‘Death to America’ who have been most opposed to the deal. They’re making common cause with the Republican Caucus.”

5. “It [military action] would likely guarantee that inspectors are kicked out of Iran. It is probable that it would drive Iran’s program deeper underground. It would certainly destroy the international unity that we have spent so many years building.”

Obama rejected the notion that military action would diminish Iran’s nuclear program more effectively than a diplomatic approach. He cited studies that found that military action would set the program back by at most a few years—“a fraction of the limitations imposed by this deal.”

6. “Without this deal, the scenarios that critics warn about happening in 15 years could happen six months from now. By killing this deal, Congress would not merely Iran’s pathway to a bomb, it would accelerate it.”

He stressed that while aspects of the deal expire in 15 years, the “prohibition” on Iran obtaining a nuclear weapon, the ban on “weapons-related research” and the international inspections are all permanent. He argued that if Congress rejects the deal, the U.S. loses the permanence of those pieces.

7. “This deal is not just the best choice among alternatives. This is the strongest nonproliferation agreement ever negotiated, and because this is such a strong deal, every nation in the world that has commented publicly, with the exception of the Israeli government, has expressed support.”

8. “Unfortunately, we’re living through a time in American politics where every foreign policy decision is viewed through a partisan prison, evaluated by headline-grabbing soundbites, and so before the ink was even dry on this deal, before Congress even read it, a majority of Republicans declared their virulent opposition. Lobbyists and pundits were suddenly transformed into armchair nuclear scientists.”

He said none of the arguments against the deal “stand[s] up to scrutiny.”

9. “If Congress kills this deal, we will lose more than just constraints on Iran’s nuclear deal or the sanctions we have painstakingly built. 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.”

This article has been corrected to reflect that the “It” in the 5th quote referred to military action, not the deal.