Behind the agreement with the Taliban that enabled the American withdrawal from Afghanistan, writes Lorenzo Vidino, is a tacit understanding that has emerged in the past six or seven years between the U.S. and various jihadist groups:

The roots of the unspoken pact can be traced to the second half of 2014, when Washington assembled an international coalition to fight Islamic State. To jihadist strategists—and most people in the region—the rationale behind U.S. intervention was clear: Islamic State faced military attacks not when it conquered a territory the size of France between Syria and Iraq and ruled it with medieval barbarity, but only when it began beheading Westerners in Hollywood-style video productions and attracting thousands of Western foreign fighters who, from the safety of the caliphate, issued threats against their home countries.

The lesson was clear: lay low, don’t behead Westerners, don’t plan attacks in the West, and Washington lets you be. . . . Few in Washington would dare articulate it in these terms, but a deal that allows the United States to spare lives and money by entrusting “moderate jihadists” to govern spaces that seem to be ungovernable by any other force is a form of realpolitik that appeals to many. If it is accompanied by a narrative that paints “moderate jihadists” as an authentic expression of the local population and is sprinkled by occasional condemnation of human-rights abuses or even some toothless sanctions to clean one’s conscience, it all seems quite reasonable.

But there are solid reasons to temper enthusiasm for this deal with the devil. . . . [M]ost importantly, its fatal flaw is in the deal’s underlying assumption. Dividing the jihadist movement into “moderates” (the Taliban, and even al-Qaeda) Washington can do business with and extremists (Islamic State) that are the only real enemy is a misguided approach.

A more fitting categorization is between gradualist and impatient jihadism, the former pragmatically willing to bend its strategic posture temporarily to attain goals while the latter is more uncompromising. Gradualist jihadism is not more moderate but simply tactically smarter, adapting in the short term so as to be in a better position to do what is in the DNA of all jihadists: destabilize the larger region and attack the West. The difference between the two is not so much in the end goals but in the time frame.

In 2003, the Libyan dictator Muammar Gaddafi, spooked by the American display of might in Iraq, decided to destroy or surrender his entire nuclear program. Informed observers have suggested that the deal he made with the U.S. should serve as a model for any agreement with Iran. Robert Joseph provides some useful background:

Gaddafi had convinced himself that Libya would be next on the U.S. target list after Iraq. There was no reason or need to threaten Libya with bombing as Gaddafi was quick to tell almost every visitor that he did not want to be Saddam Hussein. The images of Saddam being pulled from his spider hole . . . played on his mind.

President Bush’s goal was to have Libya serve as an alternative model to Iraq. Instead of war, proliferators would give up their nuclear programs in exchange for relief from economic and political sanctions.

Any outcome that permits Iran to enrich uranium at any level will fail the one standard that President Trump has established: Iran will not be allowed to have a nuclear weapon. Limiting enrichment even to low levels will allow Iran to break out of the agreement at any time, no matter what the agreement says.

Iran is not a normal government that observes the rules of international behavior or fair “dealmaking.” This is a regime that relies on regional terror and brutal repression of its citizens to stay in power. It has a long history of using negotiations to expand its nuclear program. Its negotiating tactics are clear: extend the negotiations as long as possible and meet any concession with more demands.