LONDON — In World War I, more than 90,000 soldiers died from chemical gases. Their deaths tended to be horrific, and they were often drawn out and painful. The general revulsion the gases caused spurred most of the world to sign the Geneva Protocol in 1925, essentially banning the use of chemicals in warfare.

Most reports agree the Syrian government released Sarin, a nerve agent, on the nation’s capital of Damascus Aug. 21, effectively killing more than 1,000 people and violating the international law laid out by the United Nations. The question then becomes simple: Does the Syrian government deserve to be punished, and if so, by whom?

Russia, one of Syria’s closest allies, has the power to veto resolutions from the U.N. Security Council, which will almost certainly stop any U.N. decision to intervene, should they choose to make it. The choice now rests in the hands of individual nations.

The leaders of both the United States and the United Kingdom have publicly announced support for military action in Syria. But while the U.S. Congress has yet to vote on the decision, the U.K.’s Parliament voted down the measure Aug. 29.

David Cameron, prime minister of the United Kingdom, expressed disappointment in Parliament’s vote, but promised not to use royal prerogative to order the military into action.

“I strongly believe in the need for a tough response to the use of chemical weapons,” Cameron said. “But I also believe in respecting the will of this House of Commons ... It is clear to me that the British Parliament, reflecting the views of the British people, does not want to see British military action.”

Despite President Obama’s determination that the United States should act in this crisis, public opinion polls suggest most of the nation disagrees, and almost two-thirds of Congress have declared themselves opposed to action.

“These kinds of interventions are always unpopular because they seem distant and removed,” Obama said in a news conference after the G20 summit. “I’m not drawing an analogy to World War II other than to say when London was getting bombed, it was profoundly unpopular both in Congress and around the country to help the British. That doesn’t mean it wasn’t the right thing to do.”

Strictly speaking, Obama’s proposed plan to punish Syrian President Bashar al-Assad’s use of chemical weapons breaks international law. The U.N. charter authorizes military action on the part of individual nations only in the case of self-defense. As the Syrian crisis is internal, there has been no direct threat to the United States’ security.

Safia Swimelar, an associate professor of political science and policy studies at Elon University, said although international laws are outlined clearly, enforcement tends to be muddled.

“There is a gray area of international law and changes have been occurring in the last two decades so that there has been some acceptance of using force for humanitarian purposes and to preempt possible terrorist attacks, but this still should have the support of the U.N.,” Swimelar said.

Obama has ultimate control of the U.S. military, and he may choose to make a limited strike even if Congress votes otherwise. He may choose to approach the situation from another angle.

“If Congress votes no, which seems likely, I can see Obama saying we can’t act militarily,” Swimelar said. “This may be a good outcome to encourage all sides to push much harder for a non-violent diplomatic solution.”

Most of the major players in the United Nations will be asked to make a decision in the next few weeks and ultimately choose a side. Congress is set to vote September 9, and its decision has the potential to affect international relations beyond those with Syria.

“The problem is that Assad is already in major violation of international laws himself, so a unilateral attack by the United States, though technically illegal, could be argued by international lawyers to be legitimate since it is responding to other violations of the law,” Swimelar said.