Two years ago, the United States led its fellow P5+1 (China, France, Russia, the United Kingdom and the United States, plus Germany) world powers in negotiating the Joint Comprehensive Plan of Action, otherwise known as the Iran Deal. Last week, in a purely political move, President Trump announced his decision to “decertify” the deal, claiming it is no longer in the national security interests of the United States.

This “decertification” appears to be engineered by longtime opponents of diplomacy with Iran who disregard the deal because they believe it did not go far enough to address Iran’s continued funding of terrorism, testing of ballistic missiles and oppression of its citizens.

These concerns about Iran’s behavior are valid. However, the Iran Deal was not geared toward addressing them; instead, negotiations were focused on keeping the most dangerous weapons out of Tehran’s hands, fully anticipating that more work would be necessary to tackle the other bad behavior by Iran across the Middle East.

No evidence exists that suggests that this denying of Iranian compliance in order to pursue “a better deal” will fulfill the aims of those in the White House and Congress who support decertification. After all, the deal is working as designed.

Since its implementation, the Iran Deal has seen 17,000 centrifuges and 95 percent of Iran’s highly enriched uranium stockpile removed and Iran’s only plutonium reactor disabled. Meanwhile, the world’s best nuclear inspectors watch Iran’s entire supply chain — from the mines to the laboratories — so that we do not have to trust in Iran’s compliance.

Current and former diplomats, the U.S. intelligence community, our allies abroad, and Trump’s own top military officials — including Defense Secretary James Mattis and Joint Chiefs of Staff Chairman Joseph Dunford — have all verified these achievements and advised the president to certify the deal, yet he refuses to do so.

Two outcomes from this reckless decision are possible as Congress begins a 60-day review period to consider action.

First, they can choose to reinstate sanctions that were lifted per the agreement or implement new sanctions. Reinstating old nuclear sanctions on Iran for non-nuclear reasons, however, is a violation of the agreement.

Second, new legislation sponsored by senators Bob Corker, R-Tennessee, and Tom Cotton, R-Arkansas, proposes to amend the Iran Nuclear Agreement Review Act — a 2016 law designed to give Congress oversight over the deal. Unfortunately, the terms the senators are proposing effectively modify the deal’s terms, demanding further concessions from the Iranians and threatening U.S. sanctions if they don’t abide.

Either course results in the United States breaking the deal — with serious consequences.

Our diplomatic credibility on the world stage would be destroyed by a clear failure to keep our promises. This means that negotiating any future agreements — say with North Korea — will become all the more difficult. Moreover, in the absence of the deal, the limits and inspections on Iran’s nuclear program will vanish, heightening the risk of a deadly conflict in the Middle East.

Despite its imperfections, the Iran Deal is a demonstrably successful way to combat an aspect of Iran’s destructive behavior in the Middle East. Tough, principled and American-led diplomacy has successfully prevented an Iranian nuclear weapon — and as a veteran, I value keeping our men and women in uniform out of an unnecessary war.

Therefore, rather than risking a violation of the agreement, Congress should enforce the robust, bipartisan sanctions package it already passed and work to address the other aspects of Iranian behavior. Clearly, it is time for Congress to step up and preserve American leadership and national security by charting a responsible course forward.