Tough, principled diplomacy from the United States has produced historic results. On Tuesday, the P5+1, a coalition of world powers led by the U.S., reached an agreement with Iran that would prevent that country from acquiring nuclear weapons. Although successfully rolling back Iran’s nuclear program without risking a single American life should be hailed as a resounding success across the country, the success of our diplomats abroad has put longtime opponents of the talks in an awkward space.

Diplomacy—specifically, diplomacy with Iran—has always had its adversaries. Ever since the country was declared part of the Axis of Evil, the bottom line for a vocal minority of folks has been that Iran is simply too evil to deal with. And to be sure, these opponents have a solid point; Iran’s behavior at home and abroad is the primary obstacle to its inclusion in the international community. At the end of the day, pretending adversaries don’t exist isn’t how a responsible superpower engages with the world—just as we stared down the Soviet Union at the height of the Cold War, so we chose to do with a belligerent Iranian regime.

The good news is that this agreement doesn’t require us to trust Iran. Verification is the core principle of our engagement with adversaries whose interests counter our own. So all of the nuclear concessions made by Iran during this deal—a 98 percent stockpile reduction, slashing centrifuge numbers by two-thirds, and the dismantling of a heavy water reactor among them—hinge on having the best nuclear scientists in the world watching Iran’s every move. We’ve locked Iran’s nuclear program in a box, and now we’re putting a camera on it.

Opponents of negotiation—those who have been trying to derail the talks since they began—aren’t acknowledging these incredible victories, but that’s hardly surprising given their peculiar behavior throughout the process. On March 9, Sen. Tom Cotton (R-AR) led 47 other U.S. Senators in sending a letter addressed to the leadership in Iran condescendingly “explaining” America’s constitutional system and promising to undermine any deal struck with the current American administration.

While that might have been the most outrageous stunt, the rhetoric has been equally absurd. Sen. Mark Kirk (R-IL) compared chief negotiator Wendy Sherman to Neville Chamberlain in an ill-advised historical analogy. And Sen. Lindsey Graham (R-SC) rushed to CNN yesterday morning to denounce the agreement “as a bad deal, the worst possible outcome”…before admitting he hadn’t read it. Would they have stood in the Senate and decried President Reagan’s arms control agreements and written a letter to Gorbachev?

The volume and the noise isn’t just reflexive partisanship designed to grab the spotlight: it also serves to mask the fact that these Senators have no alternative to this deal. At least, no alternative grounded in reality.

How, exactly, do we get the unicorn deal that dismantles every piece of nuclear infrastructure in Iran and forces their scientists to forget everything they know about the periodic table of elements? Opponents of negotiation often say additional sanctions will force a better deal with the Iranians. But this is a false choice. The current sanctions regime was effective in forcing the Iranians to the table because it involved many of the world’s major powers. Adding sanctions when a deal was in reach would have upended the sanctions regime, which no amount of American sanctions alone could replace.

The uncomfortable (and unpopular) subtext of many opponents’ public statements is clear: Despite the immense amount of blood and treasure spent in Iraq, some have still not learned the lesson that wars in the Middle East fought in the name of nuclear non-proliferation are best avoided if there is a better option.

In discussing alternatives to negotiation, these folks either tend to avoid questions about the need for military action or make an all too familiar “it-would-be-a-slam-dunk” style argument, suggesting that a few days of air strikes would be more effective in bringing about a peaceful and permanent solution than months of tough negotiations and indefinite intrusive inspection of Iran’s facilities.

Virtually all of America’s serious military experts believe that surgical air strikes would at best set back Iran’s program by a few years. This suggests an endless pattern where the U.S. will have to continue putting our pilots at risk. As bombing a country doesn’t generally put them in a talking mood, it’s unlikely that an opportunity would arise to negotiate a better deal than the new agreement.

I work and interact with many veterans and security professionals on a day-to-day basis, folks whose entire professional lives have been spent trying to undo the rush to battle in Iraq. Most of them are inclined to avoid needlessly putting our men and women in uniform back into harm’s way.

If Iran violates this historic agreement, we’ll know because of the intrusive inspections regime this agreement puts in place—and those inspections do not sunset in 10 years, despite what some have said. All options will be on the table—whether that violation happens a month, year, or decade from today. But pursuing military action that will not actually roll back Iran’s program is plainly a worse option than a robust, enforceable agreement that closes off every Iranian pathway to a nuclear weapon.

The two thirds of Americans who support tough negotiations over another unnecessary war can only hope that those prone to knee-jerk reactions in the U.S. Senate stand down in the face of this historic agreement. We set out to prevent Iran from becoming a nuclear power, and we’ve achieved that—for which our diplomats deserve praise. Now, the hard work of verification begins, with America leading the world in the tough but principled way that is our standard.

Brendan Gilfillan is the Director of Communications and Public Affairs for the Truman National Security Project.