Shortly after last month's Paris terror attacks, I wrote in this column of my newfound unease at commuting in New York. A month on, America has a new tragedy of its own and anxiety here is all the worse.
Since the San Bernardino attack, conversations about terrorism and the prospect of being killed in an attack have brought a macabre weight to American life I've not experienced before. For days after the attack, Americans obsessed over the motive: terrorism or a massacre? As if the answer meant something to the dead.
Barack Obama deemed it necessary to broadcast a reassuring message on Sunday night primetime, his first from the Oval Office since 2010.
Friends in New York have admitted they're as good as packing themselves. I've had a couple of nightmares.
Such is the extraordinarily disproportionate impact of terror.