Associated Press
Iranian President Mahmoud Ahmadinejad, left, and his close ally Esfandiar Rahim Mashaei wave to journalists as they arrive at the election headquarters of the interior ministry.

TEHRAN, Iran — By now, President Mahmoud Ahmadinejad is well-accustomed to enduring blows from Iran's ruling clerics as his reputation fell from favored son to political outcast. But their intended parting shot — barring his chief aid from the presidential race — may be just the opening act in Ahmadinejad's reinvention as a self-styled opposition force.

Ahmadinejad vowed Wednesday to use what clout he has left to challenge the ruling by election overseers to block his protege from the June 14 ballot to pick Iran's next president.

His chances of success are likely very small. Yet his refusal to accept the ruling clerics' judgment is a sign that his political transition is already underway from an insider at odds with the leadership to an outsider with the potential to be even more disruptive.

"The election will be as much about what Ahmadinejad does as the candidates running to replace him," said Patrick Clawson, director of research at the Washington Institute for Near East Policy. "He still remains in the spotlight."

Ahmadinejad, once seen as firmly within the theocracy's fold, is now viewed by the leadership as a troublesome maverick after trying to challenge the authority of Supreme Leader Ayatollah Ali Khamenei. The rejection Tuesday of his confidant Esfandiar Rahim Mashaei — though widely expected and greatly overshadowed by former President Akbar Hashemi Rafsanjani also being ruled unfit for the race — marks an important crossroads for Ahmadinejad.

He is left politically adrift with no clear candidate to back and a highly uncertain future after he steps down. He could seek an alliance with one of the eight candidates approved by the ruling clerics — nearly all close allies of Khamenei — by offering his still significant popular base, mainly in rural and poor areas that benefited from his government's development projects and handouts.

More likely, however, is that Ahmadinejad could try to carve out his own political movement as an alternative voice in a country facing a multitude of problems, including an economy dragged down in part by sanctions over Tehran's nuclear program.

Iran already has a range of political factions from ultraconservative to liberal-leaning. But none stand out as a credible opposition force since the Green Movement was crushed after Ahmadinejad's disputed 2009 re-election.

Ahmadinejad does not openly share its Western-looking views and is unlikely to call for bold reforms, but any political group he leads could become a powerful platform for self-promotion and to keep his successor off-balance.

Comment on this story

It also would be ultimate payback after years of pressures from the ruling system. Iran's theocracy seeks to end the internal political battles with its slate of establishment-friendly candidates. Instead, Ahmadinejad could play the role of spoiler.

His comments were in clear contrast to Rafsanjani, perhaps Iran's pre-eminent elder statesman, who appeared to accept the decision by the Guardian Council, which whittled down a list of 686 hopefuls. His campaign manager, Eshagh Jahangiri, told the semiofficial ISNA news agency Wednesday that Rafsanjani "will not protest" the decision despite his stature as one of the leaders of the 1979 Islamic Revolution and his 1989-97 tenure as president.