Is Washington the least useful place for the Republican nominee to be two weeks before Election Day? Probably. Certainly there are more valuable things Mr. Trump could be doing with his time — like polishing his collection of gold-plated TRUMP signs, hiking the Appalachian Trail, on the red carpet for the premiere of “Trolls, ”or seeing the Britney Spears “Piece of Me” show in Las Vegas.

He must see some value in making a quick ribbon-cutting stop in the midst of the campaign homestretch. The Trump brand is also at stake in the election. It’s possible that Mr. Trump wants to use the final weeks of the campaign spotlight to promote his brand, despite the fact that the more controversial Mr. Trump appears under campaign scrutiny, the more customers may be fleeing. If there’s anything Mr. Trump is good at, it’s manipulating controversy for personal gain while making someone else foot the bill. The Trump campaign has stopped holding high-dollar fund-raisers in the crucial final days of the campaign, leaving that work largely to the Republican National Committee.

Mr. Trump was probably not looking for votes in Washington. He finished third in the city’s G.O.P. primary, behind Marco Rubio and John Kasich, and there is a very real possibility he could finish third or even fourth in the general election here. But the District, with its measly three Electoral College votes, is hardly a must-win for either candidate.

Away from the picket line, Theresa Hill was sitting on a concrete planter wearing a Make America Great Again hat. She had driven down to Washington for the day from Pennsylvania in hopes of seeing “another historic moment” in the Trump campaign.