What made Iran want to agree to a nuclear deal that President Obama’s boasting about? It seems like it was more the sanction threats and brinksmanship that President Obama usually decries than it was his milder, supposedly conciliatory approach to diplomacy.

The deal reached between Iran and the U.S. and other nations this weekend is a pretty good one for the Persians (as has been explained here on the Corner, in NR’s editorial on the matter, and elsewhere), but Iran’s regime is not monolithic or perfectly rational, and contains plenty of elements that are loath to strike even a good deal with the U.S. While the eventual deal entailed the U.S. moving a great deal from its original demands, it also took Iran down from what they — especially their hardliners — originally wanted.

The White House has boasted that they got it done by tough sanctions, and a positive approach to engagement that was scorned and could have been thwarted by conservative rivals who kept threatening more sanctions and military force. The U.S. and EU sanctions the Obama administration eventually supported did create real problems for the Iranian regime, and forced them to seek relief. But it was the kind of constant pressure conservatives tend to praise that made the difference: The White House actually used hawkish congressmen’s threat of more sanctions to pressure the Iranians, while, as negotiations progressed, sanctions were ratcheted up and Iran’s economy continued to founder.

This deal dates back to talks begun in March between American and Iranian officials in Oman, just a month after the U.S. implemented new sanctions on the country’s oil industry. The indirect contacts via Oman go back even further — through years when the U.S. repeatedly tightened sanctions. According to a report from Eli Lake in the Daily Beast, after the June election of the ostensibly moderate Rouhani, with whom the White House wanted to work, the Treasury Department did passively, marginally ease its enforcement of sanctions. But the Iranians had already been forced to the table three months earlier (their economic crisis really got going in late 2012 when the rial tumbled). And whatever effect the alleged loosening had, U.S. policy was still strangling the Iranian economy.

Yet negotiations progressed, and the calls from Congress for new sanctions continued. Right up to, in fact, the recent Geneva meetings — to the White House’s public dismay, but their private advantage. Or so it would seem from an interesting moment in Reuters’s account of this past weekend’s negotiations:

After his trans-Atlantic flight on Saturday morning, Kerry met his Iranian opposite number Mohammad Zarif, with European Union foreign policy chief Catherine Ashton, who has led negotiations on behalf of the powers.
According to a senior U.S. State Department official, Kerry told Zarif there could be no more delay. President Barack Obama’s administration would call for even tighter sanctions on Iran unless a deal was reached now. Congress members were demanding new sanctions and the White House would join them.
Kerry made the case that “there would be no way to hold back new sanctions to give room for (a) new round and we would lead the charge for more sanctions if we did not come to agreement,” the State Department official said.

Last week, remember, the White House was condemning senators who were talking of new sanctions, saying they had to hold off talk of them in order to build trust for negotiations to go forward. Meanwhile, Kerry was letting hawkish senators play bad cop, and even saying that the White House was tempted to “lead the charge” for new sanctions if Iran wouldn’t agree to the deal the U.S. brought to Geneva, right then and there. Jay Carney did say publicly that the White House thought new sanctions should be passed if the P5+1 proposal was rejected, but the White House’s continued requests that senators pause talk of sanctions meant that they looked to the world a lot more conciliatory. In the negotiations, they weren’t: There was John Kerry in Geneva, using the fact that hawkish senators were pushing the White House toward sanctions to his advantage, and saying the president was tempted to join them.

Now, to what degree the president orchestrated this isn’t clear: Maybe he believes in private toughness but public rapprochement, or maybe he believes in being conciliatory but hawkish senators forced his hand. The effect is the same: The president got his deal by constantly ratcheting up the pressure at key moments, or allowing it to be ratcheted up by the contingency plans of more aggressive congressmen, not by offering carrots and trying to build trust. That’s an important lesson for politicians considering how to treat the ongoing negotiations over the next six months.