The attacks appear to be coordinated, possibly with the blessing of Supreme Leader Ayatollah Khamenei. He is said to have been upset by Ahmadinejad's attempts to act exceedingly independently and grab power in areas that are considered Khamenei's domain.
(For more on the dispute between Ahmadinejad and Khamenei, scroll down to previous posts.)
The latest attack -- one of the most serious so far -- comes from the parliament, which has voted to investigate reports claiming that Ahmadinejad's government gave $80 each to around 9 million citizens ahead of the disputed 2009 presidential vote.
The money is said to have been distributed as part of the "justice shares," a scheme designed by the government to help poor segments of society.
Lawmaker Mohammad Mehdi Mofateh has said that parliament's decision was made on the basis of a report by its Budget Commission that had not been released two years ago because of what he described as "sensitivities."
Two years ago, Ahmadinejad was still considered a Khamenei protégé who expressed approval for his reelection amid massive protests by the opposition, which alleged that vote was rigged. In recent weeks, however, Ahmadinejad seems to have lost his "golden boy" status.
The question is whether he will be allowed to complete his current term, which still has two years remaining.
Some analysts speculate that he might go down like Abol Hassan Bani Sadr, the Islamic Republic's first president after the 1979 revolution. Bani Sadr was impeached and fled Iran; he now lives in exile in France.
Others say Khamenei will keep Ahmadinejad in power, having taught him a lesson. But as usual, things can be pretty unpredictable in Iran.
-- Golnaz Esfandiari