WASHINGTON — Barack Obama was president earlier this year.

Really, eyewitness accounts from the period confirm this. It lasted nearly three weeks, it seems, or roughly the time elapsed since a Democrat won a Senate seat in Alabama, if memory serves, which it generally does not anymore.

That special election came before President Trump helped usher a once-in-a-generation tax overhaul through Congress, but after he recognized Jerusalem as Israel’s capital, which preceded threats to end American aid to any countries that objected — and they did, en masse, in a remarkable United Nations vote that almost certainly took place somewhere in there, right? Possibly around the time the president accused a female senator of doing “anything” for campaign contributions, touching off tremors in the #MeToo movement he helped inspire, and alleged another wide-scale conspiracy against him in the upper reaches of the F.B.I.

Or was that one over the summer? When were those hurricanes again? Oh, and the Pentagon has been tracking possible alien visitation. That definitely came up.

One year out, this may be Mr. Trump’s greatest trick: His tornado of news-making has scrambled Americans’ grasp of time and memory, producing a sort of sensory overload that can make even seismic events — of his creation or otherwise — disappear from the collective consciousness and public view.