When Iraq’s Shia militias began rising to prominence following advances made by the Islamic State (IS) terror group in 2014, the United States put Baghdad on notice that it could lose military support if Prime Minister Haider Al-Abadi did not reign in militiamen accused of stocking sectarianism.

Official US policy towards the Popular Mobilisation Force (PMF), the umbrella organisation of scores of Shia militias, was negative.

On many occasions the Obama administration threatened that the US-led coalition fighting IS would withhold support for the Iraqi security forces if the Iran-backed militias were deployed in battle, claiming that their involvement could help the militants rally Sunni residents to their cause.

Things have changed a lot since then. Another script is now running, as Washington seems to be looking favourably on a long-term enemy whom the United States and its regional Sunni allies have accused of being Iran’s proxy in the conflicts in Iraq.

The first glaring sign that Washington had found a new friend in Iraq’s Shia militias came from Brett McGurk, the Obama administration’s point man to Iraq officially known as the US Special Presidential Envoy for the Global Coalition to Counter IS.

On 21 October last year, McGurk tweeted that “the US commends progress by Iraqi security forces & popular mobilisation forces against #ISIL terrorist in Baiji.”

In another tweet he wrote “these units performed heroically over months of fighting, and we now look forward to strengthening our partnership in coming offensives.” Soon Washington dropped its former resolve, and policy began moving in an affirmative direction towards the old adversary.

Now the United States is no longer objecting to PMF participation in battles against IS, and in many operations US warplanes have provided aerial support to PMF units.

On 12 March, US consul-general in Basra Steve Walker visited the Al-Sadr Teaching Hospital in the city to pay his respects to wounded members of the PMF. The visit marked the first time a top US official had publicly met members of the Shia militias.

In June, a declaration by a state department-sponsored coalition conference in Washington officially endorsed the PMF as a partner in the war against IS.

But the most dramatic shift in the US strategy in Iraq came nearly two weeks ago when Western diplomats working closely with Washington met secretly with PMF leaders outside Iraq.

The Monitor, a US-based media outlet specialising in Middle Eastern affairs, reported on 19 August that the Lebanese capital Beirut had been the scene of a series of secret meetings between Western diplomats and UN officials and PMF leaders.

It said the meetings, arranged by “one of the UN organisations operating in Iraq,” had been held in a Beirut hotel from 8 to 11 August. A PMF delegate told the media outlet that the meetings had been requested by Western governments and insisted that they were closely coordinating the move with Washington.

A spokesperson for the PMF in Baghdad gave a slightly different version of the discussions, however. Moein Al-Kadhumi said the meetings had been sponsored by the Helsinki-based International Dialogue on Peace Building and State Building to discuss the future role of the PMF in the war against IS.

The Monitor, however, quoted the militia leader as saying the discussions with the Western diplomats “covered almost everything”.

Among the key issues the diplomats wanted to clarify was whether the tens of thousands-strong paramilitary force would be “fully merged with the Iraqi army,” as Al-Abadi has decreed.

“Our answer was clear. We will be a military force that is part of the Iraqi state, but not part of the Iraqi army,” the leader told Al-Monitor. He said the PMF delegation had made it clear that “we will be an alternative army subordinated to the state, just like Iran’s Islamic Revolutionary Guard Corps.”

The PMF leader said the Western diplomats also wanted to know if the militias were considering plans to take part in the parliamentary elections scheduled for 2018 and if they would join any political alliance or participate in the government.

“In terms of our relations with the various components of the Iraqi people, we stressed that the PMF had emerged from all of the Iraqi people,” Al-Monitor quoted him as telling the Western delegates.

“Because they insisted on meeting us alone and discussing the same issues, we deduced that the Germans were actually representing the United States in the meetings, and that this meeting was a preliminary step that would pave the way for subsequent direct or indirect contacts [with the United States],” he said.

“If liberating Fallujah brought us to Beirut, what will the liberation of Mosul bring,” asked the PMF leader, referring to last month’s recapturing of the IS stronghold in Anbar Province from the militants and their intention to participate in the battle for Iraq’s second-largest city of Mosul.

By and large, the Beirut rendezvous, which must have the blessing if not the support of Washington, was nothing less than a strategic shift in US policy towards the Iraqi Shia militias. But the exchange also underscores the militias’ cool pragmatism.

Militia leaders have often threatened that they will attack US forces in Iraq, rejecting any attempt to send more American troops to the country or to set up US military bases. Muqtada Al-Sadr, head of the Peace Brigades militia, blasted Walker’s visit to the country and those Shia officials who had welcomed the gesture.

According to US officials, there are up to 100,000 Iran-backed fighters now on the ground in Iraq. Last week Chris Garver, a Baghdad-based US military spokesman, confirmed to the US TV outlet Fox News that the fighters were mostly Iraqis, adding that the Iranian-backed Shia militia “are usually identified at around 80,000”.

At least one group, Kataib Hizbullah, is designated as a terrorist organisation by the United States.

There are thousands of Iranian-backed forces in Syria fighting in support of the Alawite-controlled regime of President Bashar Al-Assad. In addition to fighters from the Lebanese group Hizbullah and Shia militias, some of these Iranian-backed forces come from as far afield as Afghanistan, and hundreds have died fighting against Sunni rebels.

The new US approach towards the Shia militia in Iraq, however, raises three key questions far beyond the usual selective and situational relationships that have seemed to define Washington’s approach in the war against IS.

First, is the United States prepared to overcome its twitchiness and do business with the Shia militias, which have long been considered as a US enemy?

Second, is the United States readying itself for a new strategy in Iraq after the defeat of IS in which the Shias may expand, consolidate and institutionalise their power at the expense of both the Arab Muslim Sunnis and ethnics Kurds?

Third, does this mean that the United States will recognise Iraq as a playground for Iran and accept the Islamic Republic not only as the main actor in Iraq but also as a key regional superpower?

Of course, the answers to these questions will largely depend on the outcome of the war against IS and the new political landscape in Iraq and Syria that is expected to emerge. This will have broader implications for a region strewn with local conflicts that have been exacerbated by the interventions of regional and international powers.

Pragmatism, to say the least, has been the norm in the US way of doing business in the Middle East, including recasting policy to engage actors other than its traditional friends and allies.

With the Obama administration keen to snatch victory over IS before the end of the president’s term in January, Washington may think its new-found tough love approach to the Iraqi Shia militias could make that victory easier.

Yet, it remains to be seen if the next administration will embrace the new approach towards what has long been considered one of America’s most dangerous adversaries in the Middle East.

If that happens, it will represent a tectonic shift from the past, with dramatic consequences for both the region’s conflicts and US Middle East policy.