Recent crises have seen historical tensions between Iraq and Iran's highest religious leaders, who command the loyalty of millions and a deep philosophical difference, playing out on Iraq's streets and among politicians.

Iraqis living in Iran hold up posters of spiritual leader, Ali al-Sistani, during a protest against the extremist group known as the Islamic State. (photo: عطا كنا جيتي)

As popular protests calling for reform continue in Baghdad, an economic crisis looms and the national security crisis continues, a formerly mostly-hidden tension between two schools of religious thought is becoming more public.

Religious leaders in Iraq and neighbouring Iran have reacted to these different crises – but mostly by taking up positions at the opposite ends of any argument.

This is nothing new – the religious establishments in Iraq and Iran, who are supposed to lead the world's estimated over-200 million Shiite Muslims, have often differed in the past. But those differences were more likely demonstrated during dialogues about religious, ideological or political issues far from the view of local media. It is also a very sensitive subject in Iraq; nobody wants to discuss it very openly.

The origin of many of the differences between the two religious establishments, headquartered in Qom in Iran and Najaf in Iraq, is a basic philosophical disagreement about what is known as the Wilayat al-Faqih, or “Guardianship of the Jurist” in English. Basically disagreements about this subject centre on how much control the religious leaders in a country should have over the politics of that country. Should they be involved in all matters pertaining to ruling the country? Or only certain, more appropriate ones?

The Iraqi Shiite Muslim religious establishment in Najaf, headed by the Grand Ayatollah Ali al-Sistani, believes there should be separation between church and state. Al-Sistani has tended to stay out of political debates. Meanwhile the Iranian religious establishment in Qom, led by Iran's Supreme Leader, Ayatollah Ali Khamenei, prefers to see the two together, with the country's leadership informed by theology and religious law.

Unsurprisingly, the current problems in Iraq have seen the two religious leaders react quite differently. Both religious leaders have power in Iraq but it comes in different forms.

Al-Sistani has the most popular support inside Iraq – millions of Iraqis wait for his words and decisions and they will often simply obey those directives without a second thought. For example, when al-Sistani called on Iraqis to vote in elections and on the Iraqi Constitution and when he asked them to volunteer in the fight against the extremist group known as the Islamic State, thousands, if not millions, did as he said.

Khamenei doesn't have the same kind of support among the Iraqi people. Instead he commands the loyalty of a number of the Shiite Muslim militias currently engaged in the fight against the Islamic State, or IS, group, as well as many Iraqi politicians. The Iranian leadership also has the option of withdrawing it's much needed support for Iraq's military efforts against the IS group.

The militias that are affiliated to Khamenei include the League of the Righteous, the Badr organization, the Khorasani Brigades, Hezbollah in Iraq and Harakat al-Nujaba. These factions do not acknowledge al-Sistani's authority and affiliate themselves with Khamenei and Iran, who are thought to fund and equip them.

Another method being used by the pro- Khamenei lobby is to promote the Iranian view on the “Guardianship of the Jurist” issue inside Iraq, and more specifically, in Najaf. A year ago, the Iranians opened an office in Najaf to hand out financial aid to religious students and scholars in the city, in much the same way that al-Sistani's office does. The Iranian lobby also seeks out Iraqi clerics who are more enthusiastic about Khamenei's ideas on the subject than al-Sistani's.

The tension between the two religious authorities and their various affiliates has become more obvious during various current events.

For example, up until now, al-Sistani has preferred to refer to the mostly-Shiite Muslim militias with the term “volunteers” during religious speeches, given on his behalf by other clerics every Friday in the holy city of Karbala. This is because volunteers will go back to their homes and jobs, or they would join the official army, after the crisis has passed. They won't remain paid members of an unofficial army beholden to nobody.

Al-Sistani also supports the idea of a National Guard, an idea that was supposed to bring disparate groups of fighters from around the country together to fight in their own provinces and to protect their own people. This would see unofficial militias join the official Iraqi army under the control of the state. However some Shiite Muslim militias - especially those allied with Iran - oppose this idea, saying they want to remain independent.

Politically Iraq's Shiite Muslim parties are also split between the two religious authorities. Several – including the Islamic Supreme Council, the Sadrist movement and sections of the Dawa party, the party to which current Prime Minister, Haider al-Abadi, belongs – support al-Sistani.

Other sections of the Dawa party, which also count former Prime Minister Nouri al-Maliki among their members, as well as the Badr organization prefer Khamenei. It is also clear that al-Maliki enjoys support from Iran.

Three days after the release of an investigation into how the northern Iraqi city of Mosul fell to the extremist Islamic State group, al-Maliki met with Khamenei in Iran; al-Maliki got a lot of the blame for the rout in Mosul but Khamenei continues to praise his stand against the extremists.

Two days after al-Maliki met with Khamenei, al-Sistani criticized al-Maliki, albeit in a more indirect way; however everybody knew who he was talking when he told news agency, AFP, that, “the politicians who had ruled the country during the past years bear most of the responsibility for what is happening now.”

Another bone of contention has been recent popular protests that have drawn thousands of Iraqis to the streets. They have demanded reform, an end to corruption and better state services and employment opportunities.

During recent demonstrations, some of the Iran-affiliated militias were suspected of trying to hijack the protests in order to unbalance the government headed by al-Abadi. Some of them were calling for political reform that would have taken power away from Iraq's Parliament and given it to a President – most likely Iranian favourite, al-Maliki.

However al-Sistani came out against this idea very publicly, saying that he supported Iraq's Prime Minister and any reforms he chose to institute. Those reforms needed to be carried out according to the Iraqi Constitution and through the Iraqi Parliament, al-Sistani's spokesperson told the country.

This was seen by many as a clear response to the pro-Iran factions in the country.

After this, senior Iranian officials began to criticize the demonstrations. The Chief of Staff of Iran's armed forces,Hassan Firuzabadi, said that, “the demonstrations were being instigated by certain, well-known groups and sometimes by non-Muslims”.

A former Iranian ambassador to Iraq, Hassan Kazemi-Qomi, told an Iranian news agency that, “our information shows that certain embassies and suspicious parties are behind the demonstrations in Baghdad and those demonstrators are attacking Shiite clergy and Shiite politicians”.

Even al-Maliki spoke badly of the protests, agreeing that demonstrators were openly hostile toward Shiite politicians and clerics.

The political stand being taken by al-Sistani may have come as something of a surprise to some. For years al-Sistani has been committed to a course of non-intervention in politics, in keeping with his ideals about the separation of church and state. However recent events have apparently seemed too serious for the religious elder to stand aside. He has already been accused by Khamenei's supporters of betraying the Shiite side by advocating dialogue with Iraq's Sunnis and warning of the dangers of Iraq being forced into partition.

The question now is whether this tit-for-tat fight between the two religious authorities will worsen.

Some have suggested Iraq's political scene, and the way Iranians play within it, are a reflection of the way Iran's own political scene is being split between hardliners like Khamenei and moderates like Iranian President Hassan Rouhani.

Other experts have argued that, although Iran will always play a role in its neighbour's affairs, it can never be as powerful as the local authorities – after all, the two countries have different cultures and languages. “Most Iraqis don’t speak Farsi, most Iranians are not Arabs and nationalism remains a potent dividing force on both sides of the border,” one analyst told Bloomberg recently.

Those who wish to see the political process play out peacefully – or at least, as peacefully as possible - in Iraq can only hope that the home team's clerics win this, and the next, round.