Today, Donald Trump is marching the US toward war with Iran, but without making a case for why Washington should attack and whether Iran poses a threat to Americans that would justify the risks of military action. Trump has ordered the largest US military build-up in the Middle East since the Iraq invasion in 2003. To be sure, Trump has broadly described concerns over a supposed nuclear threat. But unlike in the lead-up to that war, when the Bush administration secured approval from Congress for an attack and spent months promoting its false argument that Iraq was developing WMDs, Trump and his top aides aren’t bothering to make clear why they might bomb Iran or what, exactly, the US hopes to achieve.