Editor's Note: (Frida Ghitis is a world affairs columnist for The Miami Herald and World Politics Review, and a former CNN producer and correspondent. Follow her @FridaGhitis. The opinions expressed in this commentary are hers.)

(CNN) Early this year, an unmarked airplane flew to Iran, its belly filled with a most unusual load: mountains of cash. U.S. officials had gone to great lengths to collect $400 million and then ship it, stacked high on cargo pallets, as payment to the Iranian government. At almost exactly the same time, Iranian security operatives released four American prisoners, including The Washington Post's Jason Rezaian.

Though news of the secret flight was only recently reported by The Wall Street Journal, it is common knowledge that at the time of the prisoner -- or hostage -- release, the United States also agreed to make a $1.7 billion payment to Iran. The $400 million shipment was to be the first installment in that payment.

Despite Obama administration denials, the transaction looks very much like a ransom, adding one more disturbing layer to what was already a troubling and secretive agreement, and ensuring that relations with Iran, and the agreement over its nuclear program, will remain near the top of the agenda for the next president.

Indeed, in January, when the deal was announced and the hostages released, many complained that the Obama administration was paying a ransom. The White House vehemently denied it, explaining that the $1.7 billion figure had nothing to do with the prisoners. Furthermore, it argued it was a good deal for the United States, settling a $10 billion claim filed by Iran at an international tribunal in The Hague over Iranian funds frozen in 1981, a matter separate from the much larger sums involved in the agreement to dismantle Iran's nuclear program.

But is the White House telling the truth? State Department Spokesman John Kirby has repeated the Obama administration's denial, stating that the talks about settling the frozen assets claim and freeing the imprisoned Americans were conducted by entirely different negotiating teams.

That explanation, however, is hard to swallow. A large cash payment at a time of a prisoner release looks precisely like a ransom payment. And that's what the Iranian commander of the dreaded Basij militia called it when he said the money "was in return for the release of American spies." If Iran thinks it was ransom, then for practical purposes it was.

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Historically, the United States has refused to pay ransoms because it did not want to encourage future hostage situations. However, since the release of the last batch of prisoners a few weeks ago, Iran detained Robin Reza Shahini, a dual U.S.-Iranian citizen, who traveled there to visit his mother, becoming the third U.S. citizen currently imprisoned by the regime.

Though we may never know the details of what was said by negotiators in working on the Iran nuclear deal, the hostage matters and the frozen funds from 1981, the picture of forklifts moving pallets loaded with mountains of euros and Swiss francs, "Breaking Bad"-style, adds to the image of U.S.-Iran negotiations as a cloak-and-dagger operation in which Iran continues to run circles around the United States.

Adding to suspicions, there seems to be a great deal still unknown about the nuclear agreement. Recently, The Associated Press published an article about what it described as a confidential document easing key restrictions on Iran's nuclear activities, which, it said, could allow Tehran to build a bomb before the deal expires.

Since the nuclear deal was reached, Iran's spending on its military has grown exponentially. That has allowed it to help its ally, Syrian dictator Bashar al-Assad, and the Hezbollah militias gain the upper hand in the Syrian war. Worse yet, just this week the country's supreme leader, Ayatollah Ali Khamenei, stoked conspiracy theories, blaming the United States for the failed coup in Turkey and warning that negotiations with Washington on regional issues would be "a lethal poison."

Iran has also stepped up its missile program, which U.N. resolutions had banned in addition to proscribing the nuclear program. After all, developing missiles capable of carrying warheads is a key requirement for a country seeking to develop a nuclear arsenal.

Despite recent Iranian military spending and political rhetoric, the Obama White House views the nuclear deal as its paramount foreign policy accomplishment. And Secretary of State John Kerry has awkwardly traveled the world urging countries to invest in Iran, which remains the world's foremost state sponsor of terrorism.

Persuading Iran to dismantle what world powers were convinced was a program aimed at building nuclear weapons was unquestionably a worthwhile cause. That was, in fact, the purpose of the sanctions. But it's difficult to escape the impression that America negotiated weakly even with its strong hand.

Not surprisingly, the would-be occupant of the Oval Office, Republican presidential candidate Donald Trump seemed to rejoice in the news. He tweeted about "incompetent" Hillary Clinton's involvement in the Iran negotiations, labeling the payment a "Scandal!" Clinton was secretary of state when the nuclear talks started, but she was long gone when negotiations dealing with the $400 million payment began.

Trump certainly thinks of himself as the better negotiator -- and perhaps one who would have succeeded in getting further Iranian concessions had he been president at the time of the deal. Unfortunately, the man who co-wrote Trump's best-seller "The Art of the Deal, Tony Schwartz, calls the presidential nominee a "fugue of failure, a farce of fumbling and bumbling," whose childlike attention span leaves him chronically distracted, hardly ideal for complex negotiations.

And while the top security concern this election cycle is who wins the presidency, the future of U.S.-Iran relations remains of paramount importance. Under different circumstances, the details of the Iran deal should become a major topic of discussion during this presidential election, and it still deserves deep scrutiny.

What would Clinton have done differently? What does she plan to do about Iran as president? Unfortunately, the reality of this year's bizarre presidential election means the most important security question for the United States is who wins the election. But what happens to Iran after America's deeply flawed negotiations remains close to the top.