Over 22 million Yemenis are in need of humanitarian aid after enduring an ongoing civil war and Saudi naval blockade for the past three years. Saudi Arabia’s unlawful blockade of Yemeni ports violates the Fourth Geneva Convention and has created a humanitarian disaster. The Yemen Civil War began after a failed political transition during the Arab Spring in 2011. in 2010, the Arab Spring was sparked after a Tunisian vegetable vendor lit himself on fire. This dramatic act sparked uprisings, and anti-government protests sprang up in many Arab countries, including Yemen. The Arab Spring uprising in Yemen forced former President Ali Abdullah Saleh to forfeit power to his deputy, current President Abdrabbuh Mansour Hadi. The Iran-backed Houthi movement took advantage of the transition of power and seized control of the northern province Saada. Support for the Houthis grew after the new government failed to meet expectations, and the group took control of the capital, Sana’a, in early 2015. In March 2015, the Houthis were joined by security forces still loyal to former President Saleh in attempting to take over the entire country; President Hadi fled abroad after the attempted coup. Concerned with the Houthis’ rise in power, Saudia Arabia and eight other Sunni-majority Arab countries began an air strike campaign to put President Hadi back in power. The coalition received intelligence and logistical support from France, the United States, and the United Kingdom. Fighting between coalition forces, pro-government forces, and the Houthis has persisted for more than three years. Saudi Arabia’s actions in Yemen violate the Fourth Geneva Convention for the protection of civilians and Geneva Convention Additional Protocol I, governing international armed conflicts. For three years, a Saudi-led coalition has “hit weddings, market and schools with airstrikes.” The coalition imposed an air and naval blockade since the conflict began and closed all of Yemen’s ports of entry after a missile strike by the Houthi-Saleh forces on the Riyadh airport in Saudi Arabia. James Ross, Human Rights Watch legal and policy director, stated that “the Saudi-led coalition’s military strategy in Yemen has been increasingly built around preventing desperately needed aid and essential goods from reaching civilians, risking millions of lives.” Yemen depends heavily on imported food and medicine, and the Saudi-enforced blockade has had a disproportionate effect on civilians by preventing these staples from entering the country. The most at-risk population in Yemen are millions of malnourished children in desperate need of humanitarian food aid. As of November 2017, seven million people were dependent on the little food aid available to survive, and nearly a million have cholera. Roughly two million children are acutely malnourished and nearly sixteen million people lack access to clean water. Nine cities have run out of clean water since the blockade began. From March 2015 to December 2017, more than 9,245 people have been killed in the conflict. At least 5,558 of those killed were civilians, with more than 9,065 civilians injured. Saudi-led coalition air strikes were the leading cause of overall civilian casualties. In December 2017, Saudi Arabia partially lifted the blockade after an international outcry,  allowing several aid deliveries into two specific Houthi-held ports. The aid, however, wasn’t nearly enough to fill the overwhelming need for supplies in Yemen. The Fourth Convention of the 1949 Geneva Conventions establishes requirements for the protection of civilians during an international conflict. Saudi Arabia ratified the Geneva Conventions in 1968 and is bound by the obligations established in the treaty.  Under Article 23, states are required to allow free passage of medical supplies, food and other necessary items intended for use by civilians. Additional Protocol I to the Geneva Conventions, written in 1977, establishes the additional protections for civilians. Articles 48 and 52 require member states to distinguish between civilian and military objectives and to prevent unnecessary suffering by civilians during conflicts. Therefore, “a blockade is unlawful if it has the sole purpose of starving the civilian population or denying the population goods indispensable for its survival.” Under Additional Protocol I, article 54 (1), blockades violate international humanitarian law if the effects of the blockade disproportionately affect civilians, and the impact of the blockade on civilians outweigh the military advantage it provides. Saudi Arabia’s blockade of Yemen violates international law and has led to massive civilian suffering. The international community, including President Trump, has implored Saudi Arabia to lift the blockade and allow humanitarian aid into the country. If Saudi Arabia continues to violate international law by taking military action that disproportionately affects civilians, it is at risk of being sanctioned by the United Nations Security Council. Human Rights Watch has urged the United Nations to sanction all coalition leaders responsible to the unlawful blockade, recommending a travel ban and asset freeze. “Under Security Council Resolution 2216, the Yemen Sanctions Committee can designate ‘individuals or entities’ for targeted sanctions” if they obstruct the delivery of humanitarian assistance to Yemen. The committee has already sanctioned several Houthi leaders; the next steps must be to sanction leaders of the Coalition for its life-threatening blockade of humanitarian aid.