The Obama administration shipped $400 million in cash to the Iranian government on the same day last January that the ayatollahs released four American hostages.

Ask anyone to describe such a cash-for-hostages deal and they'd call the money a ransom payment. President Obama and his officials have been denying it all week, but if it walks like a ransom payment and quacks like a ransom payment, it's a ransom payment.

Obama scoffed Thursday at the very idea. The timing was nothing more than coincidence. The funds were the first installment of a $1.7 billion settlement to resolve a dispute over a 1979 arms deal that collapsed, the administration insists.

But when White House Press Secretary Josh Earnest was pressed to say the prisoners would have been released without Iran receiving the pallets of cash, he could not do so.

Even Obama's pliable Justice Department objected to the timing of the payment. But it was overruled by State. Other government officials have said Iranian negotiators demanded a cash payment to show they'd received something tangible in return for the hostages.

One of the hostages, Saeed Abedini, told the Fox Business Network that on the evening he was let go, his captors told him they had to wait for another plane to arrive before he could be freed. Was that the plane laden with cash?

Perhaps appearances are in any case more important than technicalities. So it's telling that Iran regards it as a cash for hostages deal. Iranian news media have quoted government officials, including Revolutionary Guard commanders, describing the funds as payment for the hostages.

Tehran was responding logically to incentives presented to it by Washington. If you give terrorists a nine-figure incentive in mixed currencies to kidnap foreign nationals, that's probably what they'll do. Since January, the Revolutionary Guard has arrested several dual nationals from Western countries, including two more Iranian-Americans.

They know that Uncle Sam, despite protestations to the contrary, will reach for his wallet to spring hostages free and bring them home. This quid pro quo violates the core principle not to negotiate with terrorists or pay them ransom. Even worse, it puts a price on every American's head. Terrorists and terrorist states will not be slow to learn that lesson.