AP Photo/Vahid Salemi
His possible success is being seen in some quarters as a precursor to running for Supreme Leader, the position his grandfather, Ayatollah Ruhollah Khomeini, created when the Islamic revolution overthrew the monarchy in 1979.
The younger Khomeini gave credence to this speculation when he addressed reformist political activists visiting his grandfather's mausoleum outside Tehran on August 28th.
"'I'm not saying you should not accept any responsibility in the Islamic Republic. If necessary, do anything… but if there are others, let them do the job'," Hassan Khomeini quoted his grandfather as telling his father.
"If one day it's necessary for me to do something, it would be wrong of me not to take the responsibility upon my shoulders," Hassan Khomeini said.
In the Iranian media, Hassan Khomeini's statements were widely interpreted as showing his readiness to run for the assembly, answering the call of former president Akbar Hashemi Rafsanjani, who upon declaring his own candidacy for the assembly in August, invited "all those who consider themselves righteous" to join the race.
Against this backdrop, the Iran Labour News Agency proclaimed on August 4th that the triumvirate of Hassan Khomeini, Rafsanjani and President Hassan Rohani is the most dynamic force in Iranian
Clearly, Rafsanjani and Rohani supporters are already imagining a new Khomeini to succeed Supreme Leader Ali Khamenei, who was elected after Ruhollah Khomeini's death in 1989.
REUTERS/khamenei.ir
He died suddenly on March 16, 1995, allegedly of a heart attack. But Saeed Emami, deputy head of the Intelligence Ministry who was arrested as the main culprit in the systematic elimination of dissident Iranian intellectuals in the 1990s, confessed he had assassinated Ahmad Khomeini. Ahmad's importance was not so much in his talent for politics as in his position as his father's gatekeeper: No one could access the guiding light of the revolution without his permission.
Amid the revolutionary turmoil of 1979, Rafsanjani soon realised Ahmad Khomeini's importance and began tempting him with positions such as general secretary of the Islamic Republican Party, which Rafsanjani directed.
Rafsanjani even persuaded Ahmad to run for president against the secular Abolhassan Bani-Sadr, the main candidate. On both occasions Ruhollah Khomeini expressly forbade his son to accept political or executive responsibilities.
The elder Khomeini believed that so long as his clan kept free of such involvement, it would be above factional disputes and unlikely to be held responsible for the failure of the executive branch in delivering on promises made to the Iranian people.
Accepting executive responsibility would mean being asked why God's "Republic on Earth" has unemployment, a rickety public health service and, long after the 1980-88 war with Iraq, meat rationing.
Rafsanjani's scheme seems to have worked. Throughout the 1980s Ahmad Khomeini helped him systematically destroy his political rivals by simply denying them access to his ageing father.
In return, Rafsanjani may well have promised Ahmad the mantle of leadership after the revolutionary patriarch died. But when it came to the crunch, Rafsanjani supported the seemingly weaker Ali Khamenei as successor in 1989.
To the world at large, Ahmad Khomeini welcomed Khamenei's leadership. But he was plotting revenge.
Thomson Reuters
There was even a report that a group of Ahmad Khomeini loyalists within the Islamic Revolutionary Guards Corps (IRGC) seized control of a missile battery in southern Iran seeking to target US military forces in Saudi Arabia to start a war that could help Khomeini's son seize power in Tehran. The plot was foiled by Mohsen Rezaei, then the IRGC commander.
Ahmad disclosed that his father had been against continuing the war with Iraq after Iranians liberated the south-western city of Khorramshahr in 1982. The war, he implied, only continued because Rafsanjani and others wanted to consolidate their power.
A few days before his mysterious death, Ahmad Khomeini accused the regime of betraying the ideals of his revered father. Hassan Khomeini may well enjoy Rafsanjani's support in running for the Assembly of Experts but his father's fate no doubt weighs heavily on his mind.