WASHINGTON — Donald J. Trump came to Washington on Thursday to unify the Republican Party behind him.

That did not quite happen.

But here is what did: The political denizens showed once again that Mr. Trump, the reality TV star turned presumptive Republican presidential nominee, can animate the staid capital as much as any other city in America.

It helped that Mr. Trump’s visit happened to coincide with the National Cannabis Industry Association’s annual lobbying trip to the Capitol, and onlookers would have been forgiven for thinking that Washington had accidentally eaten the entire pan of brownies.

The least exciting part of the whole Trumpapalooza was the meetings themselves — those closed-door huddles between Mr. Trump and Republican leaders, which produced bland statements of “party unity” on both sides but little actual news.