there was no secret
The payment consisted of two categories: $400 million and $1.3 billion. The letter to Congress, informing it of the $1.3 billion, was delivered to Congress after the money was airlifted to Iran. I count it as "secret" if you don't tell someone about it until after it is done. See:
https://freebeacon.com/national-security/u-s-sent-iran-1-3b-cash-weeks-after-400m/and it wasn't a payoff.
I think that it very clearly was a payoff. Here's why.
When Iran took embassy hostages, the US froze Iran's $400M in the US.
As part of the resolution of the hostage crisis, there was an international court case to decide the disposition of that $400M. It started in the 1980's and as of Jan, 2017 (more than 3 decades) still had not produced its findings. So, there was no money owed by the US at that point.
Meanwhile, groups backed by Iran blew up numerous buildings and killed hundreds of Americans. Families of the murdered sued Iran, and courts found in their favor, ordering Iran to pay compensation. As of Jan., 2017, the amount awarded was more than $400M plus interest; and the US governments or courts ordered that none of Iran's potential $400M was to be paid back until Iran had paid its mandated compensation (which it has not yet done) to the satisfaction of the US.
As a result, for 37 years -- not surprisingly -- none of that $400 million was paid back.
Then in Jan., 2017, at a time the Obama administration was trying to conclude a deal involving Iran's development of nuclear weapons and trying to get several American hostages released, the administration decided to send Iran $400 million in cash plus another $1.3 billion in cash.
The stated purpose of that payment was to "settle a decades-old claim" that Iran had on the money, with further clarification that it wasn't payment for hostage release or payment for signing any deals.
That is a ridiculous and transparent cover for several reasons. First, there was not a court order for the US to repay anything, let alone $1.7 billion. A court case that has been underway since the '80's, with no findings yet, is very far from being a court order to pay it all back in full plus interest. Such a voluntary settlement is laughable to anyone familiar with court cases and how settlements generally work. Second, even if the court made a finding for repayment, there are actual awarded claims on that money that take precedence. Third, the claims by US citizens are more than $400M plus interest. Fourth, regarding the coincidence of nuclear deal, hostage release, and $1.7 billion in cash, "The Obama administration had claimed the events were separate, but recently acknowledged the cash was used as leverage until the Americans were allowed to leave Iran."
https://www.latimes.com/nation/nationnow/la-na-iran-payment-cash-20160907-snap-story.htmlThis, to me, seems quite obviously a payoff.
If names of presidents were changed but all other language stayed exactly the same, I feel highly confident that numerous media and people would have the opposite opinion.