Here are the politics of the Iran nuclear deal: Congress returns next week from its summer recess, and among the first orders of business will be taking up the Joint Comprehensive Plan of Action on Iran's nuclear program, recently negotiated with Iran in Vienna by the five permanent members of the United Nations Security Council plus Germany.

Opponents of the agreement had hoped to use the August break to sway undecided members of Congress. They pledged to spend millions of dollars on TV ads. They threatened to fill town hall meetings with angry, sign-waving constituents. Their intent was to build a veto-proof majority in the House and Senate to scuttle this plan, which is one of the Obama administration's signature foreign policy achievements -- reason enough for opposition for many Republican lawmakers.

It didn't happen.

Instead, yesterday, Sen. Barbara Mikulski of Maryland became the 34th senator to publicly support the accord -- meaning there are enough votes to sustain a presidential veto of any bill intended to kill it.

Now, here is a faith perspective: For Christians, this is a victory for peace and diplomacy over another bloody and destructive war. It is a time when common sense wins over bombast -- when reality wins over rhetoric.

Iran is an enemy of the United States, of Israel, and of peace. And this is a plan that will deny that enemy the chance to build a nuclear weapon for many years. Enemies are real, but reducing their capacity and danger is a goal worth achieving. When you can't completely defeat an enemy at a given point in time -- or not without other dire consequences -- smart diplomacy is better than more failed and destructive wars.

Peacemakers are not utopians. They are the best hope for reducing violence, avoiding the greatest dangers, halting the biggest threats, and moving things (even incrementally) in a better direction. They keep open the necessary and vital option of keeping our greatest conflicts from becoming bloody. We don't live in a perfect world, but in a broken and fallen world. So the role of peacemakers is crucial in keeping our inevitable human confrontations from killing more and more of us.

This is a moment when Dick Cheney's line of thinking, that any significant world problem can and should be solved by another war, could be soundly defeated. Warmongers are the ones who can't shake the habit of war, even when they are proven wrong again and again -- and the warmongers might now lose for a change.

In the past several weeks, a steady stream of voices -- current and former members of Congress, arms control experts, retired generals, admirals, diplomats, and many people of faith, including hundreds of American Jewish leaders and rabbis -- added their support for the Iran deal as the best possible option available to prevent a dangerous rogue nation from acquiring a nuclear weapon.

Their advocacy made a difference. And so will yours.

The Iran agreement certainly isn't perfect. No product of difficult negotiations ever is. But it prevents Iran from developing a nuclear weapon. Therefore, it strengthens America's national security and the security of our allies in the region.

And although opponents talked constantly about getting to 'a better deal,' they failed to offer a coherent one, and refused to acknowledge that our allies had no intention of reopening talks or continuing international sanctions on Iran if America walked away from this deal that many nations worked hard to negotiate.

Clearly, we should be under no illusions about the current regime in power in Tehran. From human rights, to its threatening of Israel, to its support for violent armed actors in the region, the United States and our allies must continue to keep the pressure on.

As President Obama himself said last week during a conversation with Jewish leaders,

Being for this deal does not involve pie-in-the-sky hopes about Iran. We will retain all the tools that we have to go after them ... This deal doesn't solve all the problems about Iranian behavior ... Not even close.

He's right. But what the agreement does do is prevent that Iranian regime from acquiring the most deadly weapons that world has ever known. And that is a reason to be thankful.

So what each of us can and should do is very important in the immediate days and weeks ahead. Members of Congress and Senators need to hear from their constituents. Write, email, call, tweet at your representatives that you favor diplomacy over war, and making progress toward limiting violence instead of starting more of it. Say that you favor the nuclear agreement with Iran and want them to vote FOR it. Be a peacemaker.

Jim Wallis is president of Sojourners. His book, The (Un)Common Good: How the Gospel Brings Hope to a World Divided, the updated and revised paperback version of On God's Side, is available now.