Monday could go down in history as the day we took our first step toward a comprehensive nuclear deal with Iran that prevents the country from ever acquiring a nuclear weapon.
But the peaceful resolution of international concerns about Iran's nuclear program is hardly assured.
Those of us who support diplomacy have an important role to play in preventing members of the House and the Senate -- Democrats and Republicans -- who are unwilling to give President Obama the time and political space necessary to cut a reasonable deal with Iran.
Where We Are Now
On Monday, Iran began to implement an interim deal it has made with the United States and our international partners. Iran's nuclear program is now frozen and subject to the most intrusive inspections in history.
And for the next six months, while Iran's nuclear program is halted, negotiators will try to reach a comprehensive diplomatic agreement between Iran, the United States and various world powers to prevent Iran from ever acquiring a nuclear weapon.
President Obama has been a strong voice for peace despite opposition from many within his own party. Now more than ever, he needs our strong and vocal support.
These negotiations represent the best chance in a decade to resolve this issue peacefully. But they will be tough, both substantively and politically. President Obama himself has only given the talks a 50/50 chance of success.
The stakes of these talks are high. The alternative to a negotiated deal will be either a continually growing Iranian nuclear program or another American war in the Middle East.
So we shouldn't take counterproductive actions that make the negotiations even harder than they need to be.
Yet that is precisely what hawks in both chambers of Congress are trying to do.
The Biggest Danger to Diplomacy - New Sanctions.
Among the leading political dangers to diplomatic talks is the belligerent and reckless move to impose new sanctions on Iran while negotiations are ongoing, in violation of our commitment to our international partners and Iranian diplomats as part of an interim nuclear deal.
In December, news broke that 14 Senate Democrats led by New Jersey's Robert Menendez and New York's Chuck Schumer had joined Republicans (led by Senator Mark Kirk of Illinois) in pushing a new sanctions bill (S. 1881) that would blow up diplomacy with Iran and set us on a path to war.
Initially, the new sanctions bill seemed to have momentum. But last week the momentum shifted in our favor, due in no small part to those who flooded the Senate with calls demanding that Senate Democrats not help the Republicans start another war.
And as of this morning, there are more Senate Democrats on the record opposing new sanctions at this time than there are Democratic co-sponsors of the new sanctions bill.
The National Iranian American Council, an organization that does great work supporting diplomacy with Iran, has a nice breakdown of where various senators stand on new sanctions. You can see their whip count, here.
The Second Biggest Danger to Diplomacy - Tying President Obama's Hands
Iran is currently under an extremely onerous sanctions regime. Sanctions have already crippled the Iranian economy and led to widespread economic pain, like rampant unemployment and shortages of medicine and other humanitarian supplies.
While the purpose of sanctions has never been to punish ordinary Iranians, they are the ones who overwhelmingly feel the pain caused by sanctions.
It's widely understood that if a deal is struck, the basic contours would be our agreeing to ease sanctions with a goal of ending them in exchange for a verifiable agreement with Iran that prevents it from ever building a nuclear weapon.
But some members of Congress want to move the goalposts and are trying to pass legislation that lays out the contours of what an acceptable final deal than ends sanctions would look like -- and the standards they want to establish are so unrealistic that nothing that's actually on the table would ever satisfy them.
This kind of legislation is not only dangerous if it passes. Iranian diplomats are less likely to go out on a limb and agree to potentially politically unpopular provisions if they don't believe Congress will back up President Obama by supporting the deal he cuts.
The bottom line is that Congress needs to give President Obama the space he needs to cut a reasonable deal. Legislation that seeks to tie his hands not only makes it less likely that diplomacy will succeed (which in turn makes war much more likely), it also makes it more likely that the failure of diplomacy would be blamed (perhaps justifiably) on the United States.
What Can We Do Now?
The short version is that we need to do all that we can to provide time and space for the administration to negotiate a verifiable deal that protects our interests and advances our security in a peaceful manner. Congress will try to prevent that, and it's our job to ensure that it doesn't.
In terms of strategy, we need to keep the pressure on Democrats in both chambers of Congress not to help the Republicans start another war.
Senate Democrats are our top targets. Although momentum has slowed on the new Iran sanctions bill, we remain in a dangerous position. If anything goes even a little awry in the ongoing negotiations, then move for new sanctions can quickly regain momentum.
Getting more Democratic senators on the record opposing new sanctions now is a priority, as is holding accountable those who are pushing for new sanctions.
In the House, we need to make sure Democrats don't give bipartisan support to any bill, even a non-binding resolution, supporting new sanctions or setting down markers about what an acceptable final deal will look like.
And Democrats in both chambers need to be reminded that should President Obama cut a reasonable deal with Iran, we will need them to back him up by passing legislation that reduces sanctions in exchange for a verifiable agreement that stops Iran from ever acquiring a nuclear bomb.