After U.S. Secretary of State John Kerry confirmed undeniably that the Assad regime gassed its own people with sarin, killing close to 1,500 people on August 21, Congress has to decide next week whether or not this atrocity will have consequences. On a basic level, purely for humanitarian reasons and to uphold international law on chemical weapons, the military intervention should take place. But following on the heels of the disgraceful vote in the British Parliament, the stakes now have to be framed in terms of credibility and national interests.

When weighing a strike, geopolitical interests should very much come into play.

First and foremost, the Syrian conflict is no longer a civil war but rather an international one. Indeed, this is a very large proxy war being waged by the Iran-Russia-China axis against Turkey-Saudi Arabia-Qatar, even though Saudi Arabia and Qatar are not really seeing eye to eye.

The point is that all major international players — and in particular our enemies – are, in one way or another, involved in the Syrian conflict, and advancing their pawns while the West is watching idly on the side lines. But even more worrisome is the fact that viciously dangerous non-state actors such as al Qaeda, al Nusrah, and Hezbollah are very active on the Syrian battlefield. The U.S. cannot afford the luxury of not being present on the chess board when so many of our enemies are seeing this war as the major battlefield.

Iran is spending $500 million a month to prop up Assad, and Russia is providing weapons left and right to the regime while the U.S. is missing an opportunity to play an important role in the most destabilizing conflict in the region. There is a real domino effect in the making.

Not only is the huge humanitarian crisis having disastrous consequences for the neighboring countries, but the violence is spilling over also. The conflict has spread to Iraq, Turkey — the Kurdish issue has sprung up again — and especially to Lebanon where in the past few weeks the deadliest terror attacks since the civil war in 1975 took place.

In light of this, the argument that by intervening the West is going to fuel the fire is moot. The whole region is already burning up, and the West’s action could help quell it.

By not doing anything, the West is leaving the field wide open to its enemies to win and hurt it in the medium to long term. A proxy war is being waged in Syria that has all the hallmarks of a religious war between Sunnis and Shias.

Also, the argument of not picking sides between two evils, i.e. al Qaeda and Assad, is not valid any longer. In fact this war is not a zero-sum game. Both the West’s enemies are winning: al Nusrah is making great strides within the opposition and setting mini-Islamist states and Assad’s army has been steadily gaining ground.

The argument that the chemical weapons stockpile could end up in the hands of al Qaeda does not hold water because Assad could also decide on a whim to provide some of its weapons to Hezbollah: both are terrible scenarios indeed.

Furthermore, limited military intervention could deter Iran’s nuclear ambitions. The Iranian regime will consider the international community’s response to the use of chemical weapons by the Syrian regime as evidence of its commitment to nuclear non-proliferation.

Also the U.S. will regain a little credibility since Assad’s decision to cross Obama’s “red line” will be met with actions.

The last time America was seen as a paper tiger by Osama bin Laden, the consequences were disastrous.

The status quo is not an option any longer. Iran winning, with the help of Russia and China, is the worst possible outcome. And if al Qaeda were to control Syrian territory then the West would be faced with the most threatening perfect storm in ages. If that is not enough to intervene then what is?

Olivier Guitta is the Director of Research at the Henry Jackson Society, a foreign affairs think tank in London.