If you had the choice, would you want Iran to have a stockpile of 10,000 kilograms of enriched uranium and nothing to stop them from enriching to 90 percent weapons-grade level or only 300 kilograms and none ever enriched beyond 3.67 percent; 19000 installed centrifuges to enrich uranium, and 1,000 more advanced ones, or only 5060 of the most primitive installed centrifuges; and not just for a few weeks or months but for at least a decade?

Guess what, that is the choice that members of Congress are debating. So you have to ask what are they debating?

With its current uranium stockpile and installed centrifuges, Iran potentially could build eight nuclear weapons, at least one within a few months. Under this agreement, all of that disappears for 15 years. And even then, if it went full-bore to build a weapon it would take them a year to enrich enough fissile material for one weapon. And to prevent that, all of the options available today, including using military force, would remain intact. But there would have been 15 years of neither Iran with a bomb nor anyone bombing Iran.

And there’s more. Iran has agreed never to have any weapons-grade plutonium at its Arak reactor ever; refrain from reprocessing spent fuel for at least 15 years and to ship all spent fuel from its reactor out of the country.

And there is still more. Iran has agreed to have International Atomic Energy Agency (IAEA) inspectors 24/7 at its uranium mines, its mills and every part of the uranium supply chain for 25 years and at every stage of centrifuge manufacture for 20 years.

Those are some of the reasons why non-proliferation experts argue that this is a very good agreement.

And there is no lifting of sanctions until the IAEA certifies that Iran is in fact doing what it promised. There is no signing bonus for the Iranians. Instead they have to perform before the P5+1 actually lifts sanctions. If the agreement is voted down, Iran gets a free ride—European, Russian and Chinese sanctions will fray. Iran would have no restrictions on its enrichment activities, which would be only loosely monitored. They would get to have their cake and eat it too.

Among criticisms that its opponents make, there is a technical one. Inspectors are 24/7 at the country’s declared sites, but what about when the IAEA decides there is something suspicious going on elsewhere? Then Iran and the IAEA will have two weeks to discuss the matter and try to resolve it. If they fail, the dispute comes to the eight-member joint dispute resolution commission, which has seven days to consider the complaint. However, the U.S. and its allies have a 5-3 majority on that commission so that any dispute is going to go in the U.S. direction. If Iran has not responded after three days, the U.S. could take the matter to the Security Council and force the sanctions to be reimposed. No country can veto the UN sanctions from snapping back on. U.S. sanctions reapply at a stroke of the president’s pen.

During the delay of 18 to 24 days what could Iran do to hide what it had been doing? So far as uranium work is concerned, there is very little that Iran can do to hide its activities. The traces would be there for all to see not just days later but years and centuries later. During the time period before full sanctions are reimposed nothing significant toward weapons development could take place.

There is also a non-technical criticism. Detractors argue that Iran will have the funds from the sanctions relief to further carry out nefarious activities in the region. Here one has to start by emphasizing that what it will not have is a nuclear weapon. And that makes it a much less dangerous nation, less of a threat to Israel and to the United States. In addition, Iran does not get any relief or access to the reported billions held around the world until the IAEA certifies that it has gotten rid of most of its uranium stockpile, shut down two-thirds of its centrifuges and opened the doors of its nuclear sites to international inspectors.

Finally if Iran wants to convince investors and global corporations that it is a safe place for major investments, it needs to build trust by showing that it is abiding by its obligation under Joint Comprehensive Plan of Action (JCPOA) and that it is not continuing or expanding its support for designated terrorist groups which would mean existing non-nuclear related sanctions would very likely be expanded.

There is a reason that the United States, France, the United Kingdom, Germany, the European Union, Russia and China signed on to JCPOA. It is the only and best way to stop Iran from building a nuclear bomb for at least 15 years—without war.

Schneider is senior vice president and director of the Washington office of the International Crisis Group