It was the best of deals, it was the worst of deals. On Monday, Iran allowed five American prisoners to leave the country in return for $6 billion in unfrozen oil revenues and the release of five Iranians who had been charged with violating American sanctions. It was the best deal because there’s no arguing with the glory of seeing long-suffering Americans set free. And it was the worst deal because their freedom came at a massive price—like incentivizing the taking of American prisoners.

At the New York Times, Michael Crowley and Adam Goldman wrote: “The event underscored the transactional approach to foreign policy of a president who has shown little patience for abstract ideals like alliances and stability and appears motivated instead by tangible results like arms sales and concessions like the release of imprisoned Americans. It also left some security experts concerned that the president’s focus on hostage cases might inspire foreign adversaries to capture more Americans.” Only they wrote that in August 2020, when six Americans who were freed with the help of the Trump administration attended a White House ceremony.

Today, in the Times’ write-up of Joe Biden’s prisoner exchange, Michael D. Shear and Farnaz Fassihi make no mention of impatience for ideals or alliances, but their piece does make a swap of its own, substituting “Republicans” for “experts” as the current source of skepticism: “The terms of the deal have generated intense criticism from Republicans, who accused Mr. Biden of helping to finance Iran’s terrorist activities around the world.” Republicans pounce where experts fear to tread.

But whether from sage experts or pouncing Republicans, concerns about rewarding terrorist states for grabbing Americans is legitimate. And Iran is the world’s foremost state sponsor of terrorism.

Despite there being five people on both sides of the current equation, there’s no parity here. The U.S. charges foreign suspects for alleged crimes. Iran abducts American citizens for money and leverage. Among the Iranians that the U.S. just released, for example, is one Mehrdad Ansari. In 2021, Ansari was convicted and sentenced to more than five years in prison for illegally exporting to Iran military items that could be used in a nuclear program.  Among the Americans released by Iran, on the other hand, is Morad Tahbaz, a conservationist and founder of the nonprofit Persian Wildlife Heritage Foundation, who was arrested for “contacts with the U.S. government.”

Then there’s the $6 billion. The Biden administration claimed that Iran can only use the funds for humanitarian purposes. But Iran’s president Ebrahim Raisi immediately refuted this, telling NBC News’ Lester Holt that the money will go “wherever we need it.” A Biden official then countered that the $6 billion will be held in a Qatari bank and the U.S. will monitor each transaction to ensure that the money isn’t used for proscribed activities.

What the Biden administration certainly understands, and hopes that you don’t, is that money is fungible. Even if Iran spends a $6 billion windfall in U.S.-approved sectors of its economy, it suddenly frees up $6 billion from those sectors that can be re-allocated and spent anywhere. And Iran is not known for its humanitarian largess. That money is going to weapons and terrorism.

Which is why Iran takes American hostages to begin with. The U.S. unfroze billions of dollars to release Americans from Iran in 1980. It brought a miraculous end to a horrible crisis. But it meant that Iran would eventually return to taking hostages.

The best American response is also the most coldblooded: no rewarding hostage-takers. Instead, apply pressure and be vigilant about the regime’s provocations. But, unlike Iran, we’re too humanitarian to forgo indefinitely the chance at freeing one of our own. Combine that with the wrongheaded enthusiasm for rehabilitating Iran evinced by the Biden administration, and today’s deal was inevitable. Which means, Iran won’t stop. It’s a trap. And it’s easiest to be coldblooded about it once we’ve fallen into it yet again. Experts and Republicans are right to be skeptical.