Sometimes international law is ambiguous. Sometimes not. When it comes to murdering civilians and using chemical weapons to get the job done, there are no gray areas, no fuzzy lines, no mitigating circumstances. Such practices are clearly and specifically prohibited under what's called "the law of war." That makes Bashar Assad, Syria's dynastic dictator, a war criminal. And it makes Iran his chief accomplice.
As far back as 2005, Jane's Defense Weekly reported that Iran's rulers were actively helping Mr. Assad launch an "innovative chemical warfare program" — providing technology to build equipment that would produce "hundreds of tons of precursors for VX, sarin nerve agents and mustard blister agent."
When it comes to the Islamic republic, President Trump and his advisers are under no illusions. "Everywhere you look, if there's trouble in the region, you find Iran," Secretary of Defense James Mattis said last Wednesday during a visit to Saudi Arabia.
"Iran is the world's leading state sponsor of terrorism," Secretary of State Rex Tillerson reaffirmed the same day. The clerical regime, he added, "is responsible for intensifying multiple conflicts and undermining U.S. interests in countries such as Syria, Yemen, Iraq and Lebanon and continuing to support attacks against Israel. An unchecked Iran has the potential to travel the same path as North Korea and take the world along with it."
So what's the Trump administration's strategy for checking Iran? That's still a work in progress. But some measures can and should be taken immediately. In particular, unlike his predecessor, Mr. Trump should refrain from facilitating Iran's support for terrorism and war crimes.
For example: During the final months of the Obama administration, the U.S. Treasury Department issued a license for Boeing to sell 100 new planes to Iran Air, "the airline of the Islamic Republic of Iran." Treasury also issued licenses to Airbus for a similarly sized deal. Iranian officials claim these aircraft will be used for civilian purposes only.
The evidence suggests they're lying. Emanuele Ottolenghi, my colleague at the Foundation for Defense of Democracies, has been painstakingly tracking Iran Air flights between Tehran and Damascus. There have been 768 since Jan. 16, 2016, the day that President Obama's nuclear deal with Iran, the Joint Comprehensive Plan of Action (JCPOA) was implemented. Of those 129 were on Iran Air.
Mr. Ottolenghi believes few, if any, are ferrying tourists keen on sightseeing, shopping and fine dining. He believes they are supplying military equipment and fighters in support of Mr. Assad's forces and those of Hezbollah, Iran's Lebanon-based proxy militia, which has been deployed to help defend Mr. Assad's regime.
It's worth recalling that, in 2011, Treasury "designated" Iran Air for providing material support and services to Iran's Revolutionary Guard Corps, which had itself been designated for proliferating weapons of mass destruction. Treasury particularly noted that Iran Air had been transporting "missile or rocket components to Syria."
Then, suddenly, just over a year ago, Iran Air's designation was removed. Administration spokesmen declined to explain why except to say they were acting "pursuant" to the JCPOA. An educated guess: President Obama had added a sweetener — one of many — to a deal he saw as essential to his legacy.
Decades of sanctions against Iran's civil aviation sector were lifted as well. In congressional testimony earlier this month, Mr. Ottolenghi said that from Iran's perspective, the timing could not have been better: This was the point at which the aviation sector "became vital to Tehran's war efforts in the Syrian theater."
Mr. Ottolenghi is recommending that the Trump administration, at the least, now "suspend licensing for aircraft deals while it conducts a thorough review of their role in the airlifts to Syria."
The U.S. intelligence community has the means to determine what's moving between Iran and Syria. If these flights are, in fact, military rather than commercial and civilian, Mr. Ottolenghi would urge the administration to sanction — or rather resanction — Iran's entire aviation sector. Because these would be non-nuclear sanctions, doing so would not violate the JCPOA. Airbus' license can and should be suspended as well because its planes contain key parts made in the USA.
The same week Mr. Assad used chemical weapons to slaughter more than 70 people in northwestern Syria, yet another Iranian airline, Aseman, signed yet another deal to purchase Boeing planes. Aseman's CEO, Hossein Alaei, spent most of his career in Iran's Revolutionary Guard Corps and its Ministry of Defense, a branch of Iran's government also designated for proliferating weapons of mass destruction and their delivery system. Mr. Trump should instruct Treasury not to grant a license to Aseman, either.
Executives, stockholders and lobbyists for Boeing and Airbus will not be pleased by what I've written above. But they should ask themselves: Do they really want history to record that they helped Iran Air enable Mr. Assad's mass murder of innocent men, women and children?
Under the JCPOA, Iran's rulers agreed to delay — not end — a nuclear weapons program whose existence they do not acknowledge. In exchange, they've received billions of dollars as well as permission to join the nuclear weapons club a few years down the road. What if, at that point, they're still the world's leading sponsors of terrorism, vowing genocide against Israel and "Death to America!"? Under the deal Mr. Obama concluded, that won't matter.
When it comes to the threats Mr. Obama left for his successor, none is more daunting than that posed by Tehran. In principle, Mr. Trump should be encouraging Boeing and other American companies to make a buck abroad. But as a matter of principle, Mr. Trump should not allow Boeing nor any other American companies to be in the business of aiding and abetting terrorists and war criminals.