Illustration: Liu Rui/GT

US President Barack Obama's recent call for an international alliance against the forces of the Islamic State (IS) has been warmly received by most of the targeted nations. The reason is obvious, given that the IS has not made even the slightest attempt to disguise its utter savagery and genocidal practices to the rest of the world.

Unfortunately, the IS is not the only issue confronting the world, and the US must be prepared to make some difficult choices if it is serious about forging a stable alliance to eliminate this threat.

This is especially true when considering nations that while opposing the IS, also have serious ongoing conflicts with the US.

Perhaps the most explicit example is Iran. While Tehran has been heavily engaged in supporting Baghdad against the IS, there is little coordination between Iran and the US on this issue.

In addition, the two nations remain conflicted over Iran's alleged nuclear program, with Congress recently passing an fresh package of anti-Iranian sanctions.

Coordination with Iran is a vital part of dealing with the IS in Iraq. Not only can Iran lend its formidable military might to this endeavor, it also has a great deal of influence over Iraq's Shia-dominated government.

This influence will be a vital part of forging a diplomatic solution that can help overcome Iraq's deep sectarian rifts. In fact, it is hard to see how any alliance that does not include Iran can have any hope of long-term success when it comes to eliminating the IS in Iraq.

Although direct diplomatic contact with Iran remains politically unacceptable to many individuals in both nations, the US should work to bring Iran into this coalition, while reassuring the Iranian government and people that it respects Iran's position as a major regional power.

Furthermore, the US should demonstrate its focus on the IS by refraining from passing any further unilateral sanctions over Iran's nuclear program and instead deferring to the P5+1 group on this issue. The US must also publicly acknowledge that both nations share a pragmatic and moral interest in the defeat of the IS.

But attempting to forge such a new relationship would bring Obama into conflict with powerful political factions, some of them within his own party. Obama would have to forthrightly state that the US needs Iranian aid in this issue, while also repudiating the claims that the US and Iran are doomed to eternal confrontation.

The second issue that Obama must confront is the question of Syria. Both Russia and Iran are supporters of President Bashar al-Assad, and the growth of the IS in Syria lends some credence to their position.

The hoped-for moderate opposition has failed to become an effective fighting force, and that trend seems likely to continue, no matter how much material support the US provides.

In fact, there is a credible risk that any weapons sent to the moderate Syrian rebels may simply end up reaching the IS.

While it is politically unthinkable for the US to support Assad, Obama must work on providing Iran and Russia with guarantees that their interests in Syria will be respected. Meanwhile, despite the claims of some in Congress, Iran and Russia will be needed for any long-term solution to the Syrian crisis.

Finally, the US must be willing to confront its traditional Middle Eastern allies in this affair. Some governments in this region have helped to fund the IS via private donations. As a part of any alliance, the US must focus on convincing those governments that the time has come to crack down on those individuals who have been privately funding the IS and other terrorist groups.

When attempting to forge a lasting alliance against the IS, the American people must remember that allies are not servants and will continue to have their own goals.

Working together does not mean that the US, Iran and Russia have ceased to have any other conflicts, but simply that they all recognize the common threat posed by the IS.

For US, the true challenge of this issue is not military, but the need to establish alliances based on pragmatic goals and mutual respect alike.

The author is a freelance writer based in Corona, California. charlesgray109@gmail.com