Hillary Clinton moved to press her advantage in the presidential race on Sunday, urging black voters in North Carolina to vote early as Republicans increasingly conceded that Donald J. Trump is unlikely to recover in the polls.
With a strong lead in national polls, Mrs. Clinton has been pleading with core Democratic constituencies to get out and vote in states where balloting has already begun. By running up a lead well in advance of the Nov. 8 election in states like North Carolina and Florida, she could make it extraordinarily difficult for Mr. Trump to mount a late comeback.
On Sunday, Mrs. Clinton appeared at a church in Raleigh, N.C., with mothers who have lost children to gun violence or clashes with the police. Addressing the congregation, she sounded like a candidate looking past the election to a presidency in which she would have to address a deeply divided nation.
“There are many people in our country willing to reach across the divide, regardless of what you’ve heard in this campaign,” Mrs. Clinton said. “There are people — millions and millions of people — who are asking themselves these hard questions, who want to find a way to work together to solve these problems that we face.”
Geneva Reed-Veal, whose daughter, Sandra Bland, died in a Texas jail after a traffic stop last summer, called on the congregation to make its voice heard at the polls. “If you decide not to vote, shut your mouth,” Ms. Reed-Veal said.
Both Mrs. Clinton and key Republican groups have effectively pushed aside Mr. Trump since the final presidential debate on Wednesday, treating him as a defeated candidate and turning their attention to voter turnout and battling for control of Congress.
An ABC News tracking poll published on Sunday showed Mr. Trump trailing Mrs. Clinton by 12 percentage points nationally and drawing just 38 percent of the vote.
Mrs. Clinton, who drew support from 50 percent of voters in the poll, was openly dismissive of Mr. Trump over the weekend, telling reporters on Saturday that she no longer worried about answering his attacks. “I debated him for four and a half hours,” she said. “I don’t even think about responding to him anymore.”
Karl Rove, the chief strategist of George W. Bush’s successful presidential campaigns, said Sunday on Fox News that he did not expect that Mr. Trump could pull off a comeback in the final two weeks of campaigning.
“I don’t see it happening,” Mr. Rove said.
Two outside groups aligned with Republicans, the U.S. Chamber of Commerce and the Senate Leadership Fund, have begun running television commercials in Senate races implying that Mr. Trump’s defeat is likely and asking voters to send Republican lawmakers to Washington as a check on Mrs. Clinton.
And the Congressional Leadership Fund, a powerful “super PAC” that supports Republicans in the House of Representatives, will begin running ads in the coming days that attack Democratic candidates as “rubber stamps” for Mrs. Clinton, and urge voters in swing districts to support a Republican instead.
Mike Shields, the president of the Congressional Leadership Fund, said the group had tested the message and found it effective even in areas that are likely to support Mrs. Clinton over Mr. Trump.
“There are many districts where we are going to be running ads that talk about the Democrat being a rubber stamp for Hillary Clinton,” Mr. Shields said. “In many districts, it is a very, very potent weapon to use against a Democratic candidate for Congress.”
Mr. Trump’s campaign manager, Kellyanne Conway, acknowledged on “Meet the Press” on NBC that Mr. Trump was behind in the race. She said the campaign had “a shot” at winning over undecided voters who do not currently support Mr. Trump but who dislike Mrs. Clinton.
But Mr. Trump has made little effort in recent days to deliver a sharply honed campaign message or to address the flaws at the core of his candidacy. He scheduled no public campaign events on Sunday before an evening rally in Naples, Fla., though early voting begins this week across most of the state.
In a Saturday speech that was intended to outline his closing message in the race, Mr. Trump instead began by issuing a broad threat to sue all the women who have come forward to say that he sexually assaulted them.
Ms. Conway said on Sunday that the threat was “a small piece of a 42-minute speech.”
Nick Corasaniti contributed reporting.