The New York billionaire shrugged off signs of discord within his own campaign hours after sewing up the number of delegates needed to clinch the GOP nomination, a feat that completed an unlikely rise that has upended the political landscape and set the stage for a bitter fall campaign.
"Here I am watching Hillary fight, and she can't close the deal," Trump crowed during an appearance in North Dakota. "We've had tremendous support from almost everybody."
Trump's good news was tempered by ongoing internal problems.
Those include the sudden departure of his political director and continuing resistance by many Republican leaders, including House Speaker Paul Ryan and New Mexico Gov. Susana Martinez, to declaring their support for his outsider candidacy.
At the same time, Clinton faced fresh questions about her use of a private email server while secretary of state, even as she fought to pivot toward Trump, who she warned would take the country "backward on every issue and value we care about."
The State Department's inspector general released a report a day earlier concluding that Clinton did not seek legal approval for her private email server, guaranteeing the issue will continue nagging her campaign for a second summer.
She insisted Thursday that she had done nothing wrong.
"It was allowed. And the rules have been clarified since I left about the practice. Having said that, I have said many times, it was a mistake. And, if I could go back, I would do it differently," Clinton said, according to an interview transcript provided by ABC News.
Campaigning before union workers in California, she decried Trump's anti-union comments and his proposal to deport millions of immigrants who are in the U.S. illegally.
Complicating her election challenge, Clinton's Democratic rival Bernie Sanders embraced the possibility of a one-on-one debate with Trump. The Republican said he'd "love to debate Bernie" as he faced reporters last week.
"The problem with debating Bernie," Trump noted, "he's going to lose."
Just 75 delegates short of her own delegate majority, Clinton remains on a path to clinch the Democratic presidential nomination, according to an Associated Press count. But Trump got there first.
The New York businessman sealed the majority by claiming a small number of the party's unbound delegates who told the AP they would support him at the national convention in July.
Among them was Oklahoma GOP chairwoman Pam Pollard.