Washington (AFP) - The surprise release of five Americans held in Iran has helped a vulnerable President Barack Obama put his political foes on the back foot.
On a day when the White House took the politically unpopular step of unfreezing up to $100 billion dollars in Iranian assets, the administration pulled an ace from its sleeve.
After 14 months of stop-start secret talks between senior Iranian and US officials, Tehran announced the release of four Americans in exchange for seven Iranians being released in the United States.
A fifth American, identified as Matthew Trevitick, was also released as a separate but "associated goodwill gesture."
A senior US administration official said the timing of the two developments was coincidental.
The swapped group included Americans Jason Rezaian, a Washington Post journalist, and Saeed Abedini, a Christian pastor from Idaho.
Both men have become causes celebres for Republicans who oppose Obama’s strategy of engagement with Iran.
When a deal was reached last summer to significantly scale back Iran’s nuclear program in return for sanctions relief, Obama was pilloried for leaving Rezaian and others languishing.
Republican hopeful Ted Cruz — a Christian conservative has long demanded Abedini’s release as one precondition for talking to Tehran.
In a sign of how successful Republican criticism has been, ahead of "implementation day" much of the focus was on sanctions and Iran’s return to the global economy.
Critics argued that the windfall would be used by Tehran to fund militants like Hezbollah or Yemen’s Houthi rebels.
Less noted was a report from international inspectors, also on Saturday, that precipitated sanctions relief.
The IAEA reported that Iran, after decades of massive investment, had hobbled its own nuclear program.
-- "Bluster and bombast" --
Republican attacks on Obama's policy of engagement had intensified this week as 10 American sailors were detained in the Gulf by Iran’s hardline Revolutionary Guard Navy, but not before being paraded in front of the cameras.
The White House and its allies gamely pointed to the sailors’ quick release as evidence that diplomacy is working.
It was an argument they reprised upon news that five more Americans would be released.
"For all the bluster and bombast fashionable in some quarters, today's events underscore how important -- and under-appreciated -- diplomacy is," said David Axelrod, a long-time Obama advisor.
Democratic presidential hopeful Martin O’Malley sent his own "memo" to Republican candidates. "Diplomacy beats carpet bombing," he said.
Republicans responded to the prisoner release with slightly more tempered criticism than had been seen in recent days.
"We don't know the details of the deal that is bringing them home. It may well be that there are some very problematic aspects to this deal," said Cruz, referencing Abedini by name.
Florida Senator Marco Rubio said he was happy for the families of the captives, but accused the Obama administration of "incentivizing" the detention of Americans by agreeing to a swap of seven Iranians imprisoned in the United States.
"It tells us all we need to know about the Iranian regime, that they take people hostage in order to gain concessions and the fact that they can get away with it with this administration," he said.
"I think this created an incentive for more governments to do this around the world.”
Republican frontrunner Donald Trump, who has long portrayed himself as a master negotiator, questioned whether it was a good deal.
With both Iranians and Americans heading to the polls this year, it may be too early for either side to declare victory.
According to Richard Nephew, a former US diplomat who negotiated with Iran, hardliners on both sides will be trying to "demonstrate that they remain 'tough' on their adversaries in the other capital and to appease their domestic hardliners."
At the same time there are multiple points of possible friction between Tehran and Washington.
The White House is likely to introduce new sanctions later this year in response to Iran's recent ballistic missile tests.
In multiple conflicts across the Middle East the two countries find themselves on different sides.
"Removing the nuclear issue from the table does not itself solve the problems in Syria, Yemen, or the broader sectarian conflict within the region," said Nephew.