Harris has led Trump in every Reuters/Ipsos poll since she entered the race in July, but her advantage has steadily shrunk since late September.
Trump and his allies have sought to play down the violence of Jan. 6.
Thousands of his supporters stormed the Capitol, sending lawmakers fleeing for their lives after Trump's address on the Ellipse, where as president in 2021 he told the crowd to "fight like hell" to prevent Congress from ratifying his loss.
Four people died in the ensuing riot at the Capitol, and one police officer who defended the Capitol died the following day. Trump has said that if reelected, he would pardon the more than 1,500 participants who have been charged with crimes.
"We have to stop pointing fingers and start locking arms," Harris told the Washington crowd on Tuesday and urged Americans to put divisions behind them.
TRUMP SAYS NEW YORK RALLY 'AN ABSOLUTE LOVEFEST'
In Florida earlier in the day, Trump sought to move on from the racist and other vulgar remarks made by allies at his New York rally on Sunday.
Trump did not comment on
the remarks made by speakers at the Sunday event where comedian Tony Hinchcliffe called Puerto Rico a "floating island of garbage" and disparaged Black Americans, Jewish people, Palestinians and Latinos.
Trump's campaign had said previously that the comments about Puerto Rico did not reflect the former president's views, but Trump on Tuesday called the New York event "an absolute lovefest" and said he was honored to be involved.
President Joe Biden drew ire from Trump's campaign for remarks he made about the Sunday rally during a fundraising call on Tuesday.
According to a transcript posted by a White House spokesperson on X, Biden said: "the only garbage I see floating out there is his supporter's - his - his demonization of Latinos is unconscionable and it's un-American."
Several news organizations cited the same quote but without the apostrophe.
Biden later posted on X, the social media site: "Earlier today I referred to the hateful rhetoric about Puerto Rico spewed by Trump's supporter at his Madison Square Garden rally as garbage — which is the only word I can think of to describe it. His demonization of Latinos is unconscionable. That's all I meant to say. The comments at that rally don't reflect who we are as a nation."
COURTING HISPANIC VOTERS
As Harris spoke in Washington, Trump visited a heavily Hispanic city in Pennsylvania, two days after Hinchcliffe's comments about Puerto Rico drew outrage at the New York rally.
The U.S. Census Bureau says Puerto Ricans are the largest Hispanic group in Pennsylvania, a state that holds the highest number of Electoral College votes of the seven battleground states expected to decide the election.
"I’d like to begin with a very, very simple question: Are you better off now than you were four years ago? I’m here today with a message of hope for all Americans," Trump said.
Harris, who would be the first female president, and Trump, seeking a return to office after his 2017-21 term, diverge on support for Ukraine and NATO, abortion rights, taxes, basic democratic principles and tariffs that could trigger trade wars.
On tariffs, Trump on Tuesday explicitly mentioned the European Union. "They're brutal," he said in Pennsylvania. "They sell millions and millions of cars in the United States. No, no, no, they are going to have to pay a big price."