As noted below, in the broadest sense we know why President Trump ordered the assassination of Soleimani: it was an attempt to dominate a weaker power by dramatically escalating a simmering conflict. This squares with how states act and it squares with President Trump’s personality. Yet everything we’ve seen since the attack illustrates the consequences of a hollowed out national security decision-making process and an erratic and impulsive head of state.
Unnamed Pentagon officials have now suggested that President Trump opted for a policy option (the assassination) few if any of his advisors thought he’d consider. For all my criticism of President Trump, I’m deeply skeptical of these claims. This sounds like an effort to evade responsibility for the policy options the President was given. If the idea was that it’s nuts, he shouldn’t have been offered it. Still, it doesn’t speak well about the level of planning or coordination that went into this. We also have the claim that Soleimani was killed to avert an imminent threat to U.S. lives, a claim which seems clearly not to be true.