During a 29-year absence of formal diplomatic ties with Iran, the U.S. government used many channels to gain insights about the Islamic regime''s inner workings, from CIA contacts and meetings with Iranian exiles to relayed information from friendly foreign diplomats.

But the government''s lines into Iran remain critically thin, posing a challenge for the Obama administration as it tries to track and respond to an unfolding crisis that may threaten the foundations of Iran''s theocratic regime.

Setting up talks with Iranian leaders was a signature feature of President Barack Obama''s foreign policy upon entering office. But he had made little discernible progress over the past several months before political upheaval erupted in Tehran last week over the disputed outcome of a presidential election that opposition candidate Mir Hossein Mousavi called rigged.

Washington''s lack of normal diplomatic access — both to Iran''s hard-liners and its reformers — is now handicapping the administration on at least two levels. It restricts the American view of events inside Iran, where the government has cracked down on independent media coverage of street protests. And it limits U.S. officials'' grasp of more subtle political undercurrents.