Some people are speculating as to why the government of Iran suddenly decided to release the British sailors and Marines it was holding. There are a number of reasons that have been bandied about, and the two leading contenders are that we made some sort of terrible threat, or that we caved in and bribed them. Maybe both.
I think there’s another reason. The big game here is Iran’s program to produce weapon’s grade U-235, and what they need now is time. The big danger, as they see it, is that we’ll get nasty before they have a nuclear deterrent and start bombing.
The political will to do that isn’t there yet; the West hasn’t given up on diplomacy — and that’s a good thing for Iran, because they’ve been extreme adept at stretching negotiations out, making the occasional relatively meaningless concession, sometimes yanking them back again, and in general buying lots of time for the centrifuges to run.
This news report from last September is relevant:
Iranian President Mahmoud Ahmadinejad said Thursday that his country’s nuclear standoff with the West can be solved through dialogue, while calling for unspecified "new conditions" in negotiations.
Ahmedinejad, on an hours-long stopover in Senegal en route to Cuba for a summit of the Nonaligned Movement, said the debate over Iranian nuclear enrichment could be solved peacefully.
"We’re partisans of dialogue and negotiation. We believe that we can resolve our problems in a space of dialogue and justice — together," he told reporters.
And the reason why he thinks negotiations are the way to go is that it’s Iran’s best chance of stalling until their first successful nuclear test.
The release of the British tars, especially if there was neither duress nor bribery involved, makes the Iranian government look reasonable and pliable, and it encourages those in the West who think that negotiations can convince Iran to give up its quest for nuclear weapons. That’s a solid victory for Iran.