President Trump’s sanction threat against Iranian oil should be taken seriously. Sanctions on Rusal show that he’s prepared to forego consequences, as according to Goldman Sachs, they have “dramatically affected” the aluminum market.

Since the day before Rusal was shut out of the Western financial system, April 5th, the price of the commodity jumped 21 percent on the London Metal Exchange. Currently, it is at a six-year high, and bank analysts say it may rise another 25 percent to $3,000 a ton, a level last seen prior to the 2008 crash.

In their article for Bloomberg, Julian Lee and James Boxell write, “The lack of apparent concern in the White House for collateral damage is telling, whether it’s soaring prices or the jobs and pay of Rusal employees in places like Ireland and Jamaica.”

Trump must decide whether to extend waivers that were put in place as part of the Iran nuclear deal by May 12th, only a few weeks away. Sanctions may snap back into effect and it will the president’s decision as to how they will be implemented. Trump has the ability to bring other countries on board regarding the sanctions. Legislation was introduced in 2012 to deny access to the U.S. banking system to anyone who “knowingly conducted or facilitated any significant financial transaction with the Central Bank of Iran or another Iranian financial institution designated by the Secretary of the Treasury for the imposition of sanctions.”

President Obama’s policy was to grant six-month waivers to countries showing they were cutting their purchases of Iranian crude. What happened with Rusal suggests Trump may not be so patient.

Approximately 2.1 million barrels of crude are exported from Iran each day. 30 percent goes to China and roughly a 25 percent each to Europe and India. Even if the EU does not re-impose its own 2012 ban on Iranian oil purchases, its banks, shipping companies, refiners, insurers, and ports may risk losing their access to the banking system, giving them no option but to comply.

Iran’s oil exports are at risk, in the absence of individual waivers. Lee and Boxell write, “To be sure, oil is much more important to the smooth-running of the global economy than aluminum and that might bring an element of caution into the president’s deliberations. But he might also decide that there’s a bigger issue at stake and could see benefits from his action.”

Trump, however, may believe that disruption to global physical oil flows will not last long, as the loss of Iranian exports will boost U.S. ally Saudi Arabia. The kingdom would be the primary beneficiary of the loss of Iranian supplies.