India should be urging both the U.S. and Iran not to intervene militarily in Iraq.

The Islamic State of Iraq and al-Sham (ISIS) and its allies have made remarkable inroads into northern Iraq. The contingency plans announced by the government of India, including the dispatch of naval ships, assume that the ISIS advance will continue, leading to a collapse of state authority and an ensuing chaos from which our nationals will have to be extricated. This is the worst-case scenario, and it is always wise to be prepared for the worst, but it appears that the government believes this is the likeliest outcome, which India can do nothing to prevent. These assumptions need to be thought through.

The central assumption, implicit in our planning, is that the ISIS charge will continue unchecked, but this is unlikely. The whirligig of time brings in its revenges; paradoxically, ISIS is the beneficiary of the U.S. “surge,” which was directed at its earlier avatars and deployed in the areas and towns that most Indians are now hearing of. The Petraeus strategy was to choke off local support to the Baath diehards and al-Qaeda imports he was hunting. Since in the U.S. view, Iraq was primarily a tribal society, the tribes were the water in which its enemies swam. The tribes of the Sunni triangle, where the uprising was concentrated, were therefore given a choice to join the U.S. against the rebels or be pulverised. Most chose to join, for reasons of compelling self-interest.

These Sunni tribes of the north and west, which prospered under Saddam Hussein, suffered from the rise of Shia militias in the south and east, and were excluded from power in Baghdad after his fall. They knew the surge was temporary, the precursor to a complete withdrawal of the U.S. forces that had afforded them partial protection from Shia retribution. They saw two advantages in working with the U.S. during the surge. First, they thought that if they helped the U.S. when it needed help the most, it would in gratitude ensure that their interests were protected by the government in Baghdad. If the U.S. failed them, the money and arms it was promising for their help would give them the means to defend themselves should things fall apart after it left.

Unfortunately for the Sunnis, Iraqi Prime Minister Nouri al-Maliki is rigidly sectarian. Sunnis have been sidelined and persecuted, with the U.S. either helpless or indifferent to the plight of the tribes with whose help it declared the victory which permitted its troops to leave. Sunni fears and anger have soared; their tribes were ripe for rebellion. ISIS, strengthened by its successes in Syria, came along at just the right moment. The provinces it has swept through are those where the principal Sunni tribes live. These tribes are making common cause with a group whose predecessor they first befriended and then fought on behalf of the U.S., but their target remains now, as it was then, a Shia-dominated government in Baghdad that treats them, they believe, as the enemy.

In an interview with Asharq Al-Awsat, Sheikh Ali Hatim Al-Suleimani, the head of the Dulaim, Iraq’s largest tribe, which lives in Anbar province, has described the latest events as a tribal revolt. He has claimed that tribal “military committees” have been formed in the provinces of Anbar, Nineveh, Salah Al-Din and Diyala, apart from Baghdad. The first four provinces were the ones through which what was assumed to be the ISIS advance passed like a knife through butter. They are the territories of the tribes that the U.S. assessed as the most important during its surge — the Dulaim and the Shammar in Anbar, the Al-Jubour in Nineveh and the Al-Douri in Salah Al-Din. When these tribes joined ISIS and let them through, the Shia Iraq Army had no chance, and no stomach for a fight, in what was for it entirely hostile territory.

As soon as ISIS moved out of these tribal territories, as it intruded on Kurd turf, for instance, it was repelled. Without the support of the tribes, it cannot make any further headway, and they cannot fight beyond their tribal purlieus. The Sunni tribes know that the closer they come to Baghdad, the greater the chances of the Shia tribes and militia attacking them on their flanks from Najaf and Karbala; they also know that the Army, on what is traditionally Shia heartland, will be much more resolute. It is most unlikely therefore that there will be a military collapse that will force us to evacuate our nationals, though there may be more fighting in the weeks ahead.

Even that should subside, because there are reports that ISIS has taken over to Syria the arms and equipment it captured in the advance in Iraq. Like the Taliban before it, it has now anointed its leader the caliph and promulgated a caliphate. This will be resisted by other groups, in Syria more quickly than in Iraq, because ISIS has already alienated its former allies there. If anything then, the fighting in eastern Syria may escalate, while Iraq relapses into a relative quietude.

What will continue is the daily violence in Iraq’s cities, which however has been endemic for over a year now. The final report to the U.S. Congress of its Special Inspector General for Iraq Reconstruction (SIGIR), delivered in September last year, noted that “Iraq has become significantly more dangerous … the last four months have been the most violent period in the country since the summer of 2008 …. Fighting in Syria has further complicated security in these areas … facilitated the cross-border movements of personnel from … the Islamic State of Iraq and Sham, or ISIS) …. The month of Ramadan saw more than 1,000 killed in attacks around the country … Baghdad sustained more than half of the casualties, and ISIS reportedly claimed responsibility for the attacks.”

Ramadan has just begun this year. If the past is any precedent, organised fighting may taper off in Iraq, though the government will try to retake the towns overrun by ISIS and the tribes, but terrorist violence will increase.

There is, however, one scenario that remains deeply disturbing. In this, Mr. al-Maliki’s cynical attempts to frighten the U.S. and coax Iran to help him militarily would bear fruit; the U.S. is presently unwilling but Iran will not need too much persuasion. That would be a nightmare for the Sunnis, a two-headed monster of the crusader and the Shias, against which they would unite. The Saudis, for whom Iran’s influence in Iraq is anathema, but who fear ISIS, will try to wean the Sunni tribes away from the “caliphate,” as the U.S. did, with more money and guns. The tactic has worked in Syria, where ISIS is isolated among the groups fighting Mr. Assad. This is a double-edged sword, because if Iran feels that the Sunni tribes are being armed and financed to overthrow the al-Maliki regime, rather than to drive out ISIS, it will step up its support to him and to the Shia militias, bringing about just the polarisation and fracture that must be averted.

Iran and Saudi Arabia will be watching each other like hawks across Iraq. Each needs to be reassured about the other’s intentions; neither trusts the other, nor the only present interlocutor, the U.S. There is therefore a role for a country that might bridge the chasm of distrust that divides those who are jockeying for influence in Iraq.

Our primary interest in Iraq is in its oil, which is in areas controlled by the Kurds and the Shias. The present turmoil does not affect that interest, but a full-scale civil war would. ISIS cannot bring that about; a clever manipulation of the ISIS threat by the regime in Baghdad, sucking in the U.S. and Iran on its side, and the Saudis on the other, would. With Indians held hostage, and the regime apparently unable to rescue them, there is a natural anxiety in India to look for help where we can find it; the prospect of an intervention by the U.S. and/or Iran might appear appealing, but it would be disastrous for our long-term interests in Iraq as it would for the country.

We should be urging both the U.S. and Iran not to intervene militarily in Iraq; the regime will be able to turn back the ISIS tide on its own. Simultaneously, we should urge the Saudis not to ratchet up their support for the tribes to a point where either the Iraqi government or the Iranians see it as a threat. And, with all of Iraq’s friends, we should try to prevail upon Mr. al-Maliki to rise above sectarian differences and embrace the Sunnis and their leaders as fellow citizens. In its own interest, India has a role to play in Iraq now which extends well beyond sending warships which will not be needed if its advice works and which will be almost useless if it does not.

(Satyabrata Pal is a former diplomat.)