WASHINGTON — In the uncertain turmoil of American politics, there is reassurance in the predictable pomp of the State of the Union.

Iowa bungled its Democratic caucus results on Monday night. But the trusty man in the yellow rain gear was still out before dawn in Washington on Tuesday, power-washing the sidewalk outside the Capitol.

The impeachment trial of President Trump is still in its final stage ahead of the vote on Wednesday, yet most senators intend to walk across the Rotunda to the chamber of the House of Representatives on Tuesday night to hear the annual address by the defendant — as they did in 1999 during the trial of former President Bill Clinton.