If the vote of confidence did go to Iran's parliament, known as the Majles, it could either vote Ahmadinejad out of office or choose to have him keep his seat. Analysts say it's unclear which way the heavily conservative body would go.
"If I were him I would not sit comfortably," said Trita Parsi of the National Iranian American Council.
The parliament could also impeach Ahmadinejad for performance, a move that has been raised by a narrow set of voices since before the June 12 election. In that case, says Sahimi, the Majles would vote on whether to remove him from office, then the decision would have to be approved by the supreme leader.
While conservative political dynamics have been in the forefront at the start of this week, opposition supporters are looking Thursday to stage another broad statement of solidarity. The movement's figurehead, Mir Hossein Mousavi, has called for a memorial service at Tehran's Mosalla Mosque, honoring the protesters killed in the state's violent crackdown.
The memorial marks the traditional Shiite cycle of mourning, marking 40 days since the death of Neda Agha Soltan, a 27-year-old woman who became emblematic of the slain protesters. Roughly two dozen have been killed, according to official figures, though members of the opposition place the death toll as high as 200.
Yesterday protestors in Tehran's Vanak Square met riot police and plain clothes forces, who beat them back with electrified batons, one eyewitness told ABC News. Far fewer people brave the streets than in the early days of the unrest, those who do say the movement is now an endurance race.
"The tides are changing for sure. Civil rights will win at end of the day…but it will be slow and lethargic and painful," said Farzaneh, a 26-year-old woman protester.
Opposition supporters tell ABC News they have begun organizing by locally, encouraging green graffiti of political slogans on walls and phone booths and publishing neighborhood newsletters. The nightly cries of "Allahu Akbar" continue, though some Tehran residents now shout it out of their windows, avoiding the exposure of their rooftops.
ABC News has confirmed that at least two people have been shot dead by snipers while shouting their protest.
Protesters say they are lining up with Mousavi, in support of the movement rather than of the man. Shirin, a protester who says she is fighting for a "free Iran," says the promise to make Thursday's protest a quiet, religious event rather than a political rally was too deep a concession.
"But right now we need a leader," she said. "That's why I think Mousavi is good. Now there is a leader. That's why this is going somewhere."