http://www.nytimes.com/2009/06/15/opinion/15mon1.html

There is no transparency or accountability in Iran, so we may never know for sure what happened in the presidential election last week. But given the government’s even more than usually thuggish reaction, it certainly looks like fraud.

Although a runoff was widely expected between the two top vote-getters, the polls had barely closed before authorities declared victory for the hard-line president, Mahmoud Ahmadinejad. And it was a landslide: 62.6 percent versus just less than 34 percent for the main challenger, Mir Hussein Moussavi.

We understand why so many Iranians found that impossible to believe. Mr. Moussavi had drawn hugely enthusiastic crowds to his campaign rallies, and opposition polls suggested that he, not Mr. Ahmadinejad, was the one with the commanding lead. Even more improbably, and cynically, authorities claimed that Mr. Ahmadinejad carried all of his opponents’ hometowns – including Mr. Moussavi’s – by large margins.

When protesters took to the streets in the fiercest demonstrations in a decade, the police beat them with batons. The government also closed universities in Tehran, blocked cellphones and text messaging and cut access to Web sites.

On Sunday, as protests continued, authorities detained more than 100 prominent opposition members and ordered some foreign journalists to leave the country. According to news reports, Mr. Moussavi remained in his home but was being closely watched. In a triumphalist press conference, Mr. Ahmadinejad seemed to threaten his rival, declaring that the former prime minister “ran a red light, and he got a traffic ticket.”

If the election were truly “real and free” as Mr. Ahmadinejad insisted, the results would be accepted by the voters and the government would not have to resort to such repression.

After four years of Mr. Ahmadinejad’s failed economic policies and ceaseless confrontations with the West, many of Iran’s voters clearly were yearning for a change. Mr. Moussavi promised that change; he also promised greater personal freedoms, including for women. If Tehran refuses to recognize that yearning or respect the will of its people – most of whom are too young to remember the 1979 Islamic revolution – the government will lose even more legitimacy.

The mullahs have had a tight lock on Iran up to now. But they should not forget what happened when the shah lost his people’s trust.

The elections are another potent reminder that there can be no illusions about Iran’s government and its malign intent. That is a hard political fact.

Iran’s centrifuges are still spinning and its nuclear program is advancing at an alarming rate. That is an even harder scientific fact.

We know that some in this country and in Israel will say that this election is proof that there can be no dealing with Iran and that military action is the only choice. The last thing the United States or Israel needs is another war with a Muslim state. An attack would only feed Iran’s nuclear ambitions and spur it to take even greater efforts to hide its program.

The only choice is negotiations backed by credible incentives and tough sanctions. Even if the mullahs had allowed Mr. Moussavi to win, that would still be true.