President Donald Trump is holding back from direct U.S. military intervention in Saudi Arabia’s escalating conflict with Yemen’s Iran-backed Houthi rebels, even as attacks on the kingdom’s energy infrastructure raise concerns about global oil supplies and gasoline prices in the United States.

The latest escalation has already disrupted travel and heightened security concerns in Riyadh. A large plume of black smoke was seen rising from fuel storage facilities near King Khalid International Airport after Houthi forces targeted the Saudi capital, marking a significant escalation in attacks on the kingdom.

The conflict is unfolding alongside the continuing war involving Iran, which has affected Saudi Arabia’s main oil-export routes. The partial closure of the Strait of Hormuz has restricted the kingdom’s most important route for shipping crude and has also affected other Gulf Arab producers.

Saudi Arabia is the world’s largest crude oil exporter and sends millions of barrels of oil into global markets. Any significant disruption to its exports could therefore affect international prices, including the prices American consumers pay for gasoline and diesel.

A former Gulf official told CNN that the combination of conflicts in Iran and Yemen was placing Saudi oil exports under pressure from multiple directions. Neil Quilliam, an energy and foreign affairs specialist at Chatham House, said the consequences could extend well beyond short-term changes in the price of crude.

He argued that the disruption around the Strait of Hormuz represented a structural change to regional energy security rather than a temporary market disturbance.

The risks have increased in recent weeks after Iranian-backed Iraqi militias attacked the Saudi East-West pipeline, disrupting exports from the Red Sea port of Yanbu. The pipeline provides an alternative route for Saudi oil when shipping through the Gulf is threatened.

At the same time, the Houthis have increased their military activity around the Bab al-Mandeb Strait, a strategic waterway connecting the Red Sea with the Gulf of Aden. Much of Saudi Arabia’s oil exports has been diverted through the area since the conflict involving Iran intensified.

The Houthis have also declared a blockade of Saudi shipping, increasing concerns about the security of commercial vessels and the movement of energy supplies.

According to a source familiar with the situation, Saudi Crown Prince Mohammed bin Salman personally requested U.S. military intervention after the latest setbacks but the request was rejected. U.S. Secretary of State Marco Rubio has indicated that the decision could potentially be reconsidered.

Trump, however, has said his current position is to avoid launching strikes against the Houthis while Washington continues discussions with the group.

Trump said the Houthis had contacted the United States and indicated that they did not want to fight with American forces. He also said Washington would work to resolve the group’s dispute with Saudi Arabia.

The decision not to intervene directly has generated concern inside Saudi Arabia. National Day celebrations were affected by renewed security fears, with several widely publicized drone and fireworks displays canceled or postponed.

Some Saudi residents have expressed frustration over the attacks and called for stronger U.S. support. One Riyadh resident, identified only as Khaled, told CNN that Saudi Arabia was facing a serious threat to its trade and security.

There are several reasons Trump may be reluctant to open another military front. The United States has already been involved in an extended conflict with Iran, and another campaign against the Houthis could increase the military and political costs for Washington.

There are also questions about how effective another U.S. bombing campaign would be. A previous 50-day U.S.-led campaign against the Houthis ended with a truce but did not permanently eliminate the group’s ability or willingness to continue fighting.

At the same time, refusing to intervene carries its own risks for Washington’s relationships with Gulf allies. The conflict has increased concerns among regional governments about whether the United States remains willing to provide security support during a crisis.

The economic consequences could also be significant. Although the United States is the world’s largest oil producer, American consumers remain exposed to disruptions in the global oil market.

Oil is traded internationally, meaning that a reduction in supplies from the Middle East can push prices higher even when the United States imports relatively little oil directly from the affected countries. A further decline in Saudi exports could therefore increase fuel costs for American drivers.

Higher gasoline and diesel prices could also create domestic political pressure for the Trump administration as the November midterm elections approach.

The conflict in Yemen may appear distant to many Americans already dealing with high living costs and fatigue over overseas military involvement. But continued attacks on Saudi energy infrastructure could have consequences far beyond the region by affecting global oil supplies and prices.

For Saudi Arabia, the immediate concern is protecting its energy infrastructure and shipping routes. For the United States, the growing conflict presents a difficult balance between supporting a key regional partner, avoiding another military confrontation and limiting the potential economic impact of further disruptions to global oil markets.

SOURCE: CNN, Matthew Chance, Chief Global Affairs Correspondent.