On substance, this position makes no sense. On its first anniversary, we can safely say that the Iran deal is working and that life without it would be much worse.

{mosads}First of all, the deal cannot be renegotiated. It was finalized last July by the United States, Russia, China, Great Britain, France, Germany and Iran. None of these states wants to change the agreement. If the next president were to rip up the deal, there would be nothing to replace it. The deal is the deal.

And that’s fine, because it’s a great deal. The United States is much better off with this deal than without it. Simply put, the deal prevents an Iranian nuclear bomb without endangering U.S. troops or inflaming wider regional conflict. But without this deal,Iran could resume and accelerate its nuclear program, increasing the chances of an Iranian nuclear bomb and U.S. military action.

That is why former critics of the deal are now changing their tune, even in Israel where Prime Minster Benjamin Netanyahu led the opposition. Netanyahu’s last defense minister, Moshe Ya’alon, said recently that Iran’s nuclear program “has been frozen in light of the deal signed by the world powers and does not constitute an immediate, existential threat for Israel.”

To understand just how crazy it would be for anyone to tear up the agreement, let’s compare life before the deal to life now. (Spoiler alert: you won’t want to go back.)

Before the deal: Iran had 19,000 centrifuges (machines to “enrich” uranium, a key bomb ingredient) and a large uranium stockpile, giving it the ability to produce enough bomb-grade uranium for a single weapon in about two months. (It would have taken another year or so to produce an actual bomb.) But this 2-month “breakout” period was perilously short, raising tensions in the region. There was real concern that the United States would be forced to launch a military strike to stop Tehran from amassing enough material for a nuclear weapon.

As bad as things may be in the Middle East, can you imagine adding another U.S. invasion on top of it all?

After the deal: Now, with the deal, this untenable situation has been defused. The deal has shrunk and frozen Iran’s program. Instead of two months, Iran’s breakout time is a full year, enough time to detect and disrupt any effort by Tehran to dash to a bomb.

The negotiators won this is extra time by limiting Iran’s enrichment to less than 5 percent, reducing Tehran’s installed centrifuges by two-thirds (from 19,000 to about 6,000), limiting research, and by reducing its uranium stockpile by 98 percent. These steps have already been taken (hardware has been ripped out, materials sent abroad), and will stay in place for 10 years or more, preventing a bomb far longer than military action could.

In addition, the underground plant at Fordow will not enrich uranium for 15 years and Iran’s Arak plutonium reactor has been disabled. Any plutonium (another bomb ingredient) that is produced will be shipped out of the country, and not separated from the reactor fuel.

The deal is not built on trust, but on intrusive verification. If Iran cheats, the United States will know. Tehran has agreed to the most robust inspection regime ever negotiated. The International Atomic Energy Agency (IAEA) has access to all nuclear facilities, Iran’s supply chain, and uranium mines and mills. Tehran has agreed to implement the Additional Protocol, providing access to both declared and undeclared facilities, indefinitely, including covert sites anywhere in the country.

Lastly, the deal is opening the Iranian economy to U.S. businesses. Boeing, based in Seattle, recently announced a deal worth $17.6 billion to sell 80 of its planes to Iran Air.

Given all of these benefits, trashing the deal would be a tragic mistake. It would be like tearing up a winning Powerball lottery ticket.

Without the deal, Tehran would likely accelerate uranium enrichment, reducing the breakout time. Iran would resume construction of its Arak reactor to produce plutonium. Iran may also kick out international inspectors, significantly reducing the United States’ ability to see inside Iran’s nuclear program, and increasing worst-case assumptions. This dangerous combination of shorter breakout times and less transparency would increase pressure on the United States to use military force as the only way to stop Iran from building a nuclear bomb. But a U.S. military strike would only delay Iran’s efforts by a few years while igniting a firestorm in an already-volatile Middle East.

No sane leader would “renegotiate” a deal that is working and invite such chaos.

One year into the Iran deal, it is clear that the United States and its partners have delivered a solid deal that is a historic win for global security. No one is going to tear up this agreement—it would be beyond folly. We have a golden opportunity to peacefully prevent an Iranian nuclear bomb. Could the next president do better? Not a chance.

Tom Z. Collina is director of policy at Ploughshares Fund, a global security foundation in Washington, D.C.