On Sunday, Gholam-Hossein Mohseni-Eje, Iran's judiciary spokesman, said in a news briefing that Hassan Rouhani's younger brother, Hossein Fereydoun, has been arrested.  He has been charged with getting zero-interest loans and influencing the appointment of a bank director.

Hossein has been Rouhani's right-hand man.  The timing of his arrest may be coincidental, but it comes at the anniversary of Iran's nuclear deal with six world powers, known as P5+1.  Rouhani's brother played a key role in the nuclear negotiations last year.

Anyone with a little knowledge of Iran's inner politics would have no doubt that the arrest was ordered by the supreme leader, Ali Khamenei.  Such drastic measures could not have come at a worse time for Rouhani, since he is busy with selecting his Cabinet posts.  Khamenei and the Islamic Revolutionary Guard Corps (IRGC) want the lion's share of the Cabinet posts.  It has been a pattern since the early days of Islamic Republic that the supreme leader has a final say in sections of key Cabinet positions such as minister of intelligence and Security (MIOS).

Such incidents are not uncommon in Iran's turbulent political history since the 1979 revolution.  Keep in mind that despite the May 19 sham presidential election in Iran, Rouhani is not home free.  According to Iran's constitution, the president cannot be legally inaugurated unless he has been blessed in an official ceremony by the supreme leader.  Rouhani knows this full well and has been trying to play it safe until his inauguration.  On different occasions, Khamenei has made it abundantly clear to the elected president that he has to pay his dues or else.  It has been unprecedented even by the mullahs' standards for the sitting supreme leader to directly attack the newly elected president in his public addresses.

Khamenei did not hide his utter desire to have Rouhani's main contender, Ebrahim Raisi, win the May 19 presidential race.  The IRGC stood behind the supreme leader's wishes to ensure that Raisi would win.  Vote-rigging – buying, selling, using expired ID cards belonging to the deceased, voting two and sometimes three times in various polling stations – was one of the tactics Basij paramilitary force used to put Raisi on top.  But they failed.

What still haunts Khamenei to date is the shadow of the 2009 uprising.  Those fateful days following the disputed elections that helped Mahmoud Ahmadinejad to office have been a bitter memory, shaking the mullahs' establishment to the core.  This and only this thought stopped Khamenei from pushing for a runoff election.  He knew full well that in that case, there would be another uprising.  Iranian society by all counts has zero tolerance for the mullahs' machinations, and the mullahs knew that the people could erupt with such a reckless decision on the part of the supreme leader.

On Quds Day in March – the last Friday before the end of Ramadan is marked by the mullahs' regime since the 1979 revolution, supposedly for supporting the Palestinian cause – Khamenei ordered his infamous plainclothes Basij forces to attack Rouhani and made it clear that Rouhani had to give in to Khamenei's demands.  They chanted slogans in support of the supreme leader and threatened Rouhani with impeachment.  They made sure that the newly re-elected president received the message loud and clear by reminding him of what happed to the mullahs' first president, Abolhassan Banisadr.  He was impeached by the parliament with the blessing of Ruhollah Khomeini in 1981.

Khamenei cemented his will on June 19 by ordering the Assembly of Experts – tasked with selecting the next supreme leader – to officially confirm that the "people's vote plays no role in legitimizing elected officials."  They added that it is the blessing of supreme leader that seals the deal.

According to Iran's constitution, articles 89 and 110, there are two bodies with the power to impeach the sitting president: the Supreme Court and the parliament.  The supreme leader also has the power not to "bless" the president, and that means the same thing.

Rouhani is at the crossroads of his career now: choose to give in to demands made by the supreme leader and the IRGC for the lion's share of his key Cabinet posts, such as oil minister and intelligence minister, among others, or else dig in his heels.  Standing up to the IRGC in hopes of pushing back will only add to the problems the regime faces.  The Iranian regime, which is heavily involved in at least three wars in the region – Syria, Iraq, and Yemen – is already ill positioned to afford a major power struggle at home.  Rouhani's brother is yet another pawn in the newly elected president's combat with the supreme leader. 

Mohammad Amin (@EconomieIran) is a senior research fellow for the Paris-based Fondation d'Etudes pour le Moyen-Orient (FEMO) or Foundation for the Study of the Middle East.  He has written several books and essays about the ruling theocracy, the transformation of Iran's political economy under the presidency of Mahmoud Ahmadinejad, and the rise of Islamic fundamentalism in the Middle East.