Editor’s Note: This article is one of 50 in a series about Trump's first two years as president.

It was the year’s most horrifying whodunit. Who murdered and dismembered the Saudi journalist Jamal Khashoggi inside the kingdom’s consulate in Istanbul in October? The CIA came to the view that the murder couldn’t have happened without an order from the crown prince, Mohammed bin Salman. MbS, as he is known, vehemently denies any role in killing a critical voice, a U.S. resident whose columns in The Washington Post were read all over the world.

President Donald Trump, however, isn’t sure, at least in public. “Maybe he did and maybe he didn’t,” he mused in a written statement peppered with his signature exclamation marks. Even more freewheeling in interviews, he has been clearer, saying, “I really want to believe” the crown prince’s denials. After all, there’s so much at stake: $110 billion worth of arms sales, by Trump’s estimation (one that critics say is exaggerated). American values reduced to the value of arms sales? That’s true-to-form transactional Trump.

Read: Why the U.S. can’t quit Saudi Arabia

Students of history are scrambling to find precedents in what is otherwise a long line of presidents embroidering foreign policy with far greater virtues. There’s the line attributed to Franklin D. Roosevelt (though whether he actually said it is unclear) about the Nicaraguan dictator Anastasio Somoza García, when FDR apparently said Somoza “may be a son of bitch, but he’s our son of a bitch.” American presidents don’t speak like that, at least not in public. Or they didn’t used to, anyway.