LACONIA, N.H. — In the state where he won his first primary victory, Donald Trump promised Thursday to bring manufacturing jobs back to America and told supporters that his Democratic rival Hillary Clinton doesn’t understand them.

The Republican presidential nominee, speaking at a middle school gym, took full advantage of recent comments by Clinton, who described half of Trump’s supporters as a “basket of deplorables,’’ and accused them of racism and sexism.

“Hillary Clinton slams you as deplorable and irredeemable. . . . She doesn’t understand you,’’ he said. “I call you hard-working American patriots who love your family and love your country.’’

Just hours before, Trump had laid out his economic plan in New York, saying his policies — including a $4.4 trillion tax cut — would lead to GDP growth. In New Hampshire, Trump repeatedly decried the exodus of manufacturing jobs to Mexico and China, saying he would bring such jobs back to the United States. Echoing the speech in New York, he mentioned that Ford is moving its small car production to Mexico.

“We are creating the car capital of the world in Mexico,’’ he said, “Believe me, folks, and I’m going to make sure that ends if I’m elected.’’

Trump promised he would renegotiate the North American Free Trade Agreement and create policies to stop jobs from flowing outside the country, even saying he could create an economy in which Apple’s iPhones could be made in America, rather than in China.

“ ‘Made in America,’ remember? You don’t see that very often,’’ he said.

Trump’s comments came even as Democrats have slammed him for manufacturing many Trump-branded products overseas.

Trump, with his son Eric in tow, brought his message to Laconia Middle School’s gym on a day filled with both good and bad omens for the candidate. The state’s largest newspaper, the New Hampshire Union Leader, broke with a 100-year tradition of endorsing the Republican Party’s nominee for president and, in a blistering front-page editorial, urged voters to choose Libertarian Gary Johnson over Trump. But new national polls showed that Trump is now in a dead heat with Clinton, who had commanded a substantial lead in August.

Trump also defended his children from the press on the same day his son Donald Trump Jr. was criticized for making a joke on a radio show about the media “warming up the gas chamber’’ for Republicans, which drew criticism from the Anti-Defamation League because of its association with the Holocaust. The campaign said the press was misinterpreting his remark.

“The press likes to hit them,’’ Trump said. “And they’re such good kids, but they can take it.’’

New Hampshire, though small, is an important swing state in the presidential race — as evidenced by the fact that while Trump was in Laconia Thursday evening, Democratic vice presidential nominee Tim Kaine had spent time campaigning on the Seacoast earlier in the day.

The crowd in Laconia was enthusiastic, but not as rowdy as the Trump rallies that have dominated the campaign. Speeches by other politicians, including Representative Frank Guinta, riled up supporters by reminding them about Clinton’s “deplorable’’ comments, leading to cheers through the room.

Supporters have reacted to the description with bitterness that has transformed into a sense of sarcastic pride. Thursday evening, many donned shirts proclaiming themselves “deplorables.’’ One woman, dressed head to toe in red, white, and blue, decorated an Uncle Sam hat with a makeshift “Adorable Deplorable’’ sign.

Donna and Jay Bonner, Trump fans from Florida who came to the rally during their vacation, expressed anger over Clinton’s comments.

“They think, ‘We want what’s best for people, and if you don’t agree, then you must be a bad person,’ ’’ said Jay Bonner.

Not all in the audience had made up their minds. Edna Greenfield, an independent from Laconia, said she believed there should be stricter immigration policies, for example, but she wasn’t convinced that building a wall between the United States and Mexico — as Trump calls for — would work.

Greenfield said she has been troubled by some of Trump’s comments toward women and was taken aback when he mocked a New York Times reporter for his disabilities, she said.

She’d vote for him, she said, if he were “kinder and gentler.’’

Her companion at the rally, Pete Luce, was already a devoted Trump supporter.

“He’s a jerk, but I think he’s someone who can take care of the country,’’ Luce said.

In his half-hour speech, Trump portrayed himself as a tough-talking outsider who would restrict immigration and fix failing schools.

While he repeated his claim that he would build a wall — financed by Mexico — between the United States and its neighbor to restrict immigration, he also professed support for the Latino and African-American communities.

“To the Hispanic community, I say we’re going to protect your jobs, we’re going to build up your schools, and we’re going to deliver safety and opportunity to your children.’’

Trump appeared buoyed by the recent polls that have shown him narrowing Clinton’s lead.

“In 52 days, you’re going to have a lot of happy people in this state and in this country,’’ he said.

Nicole Dungca can be reached at nicole.dungca@globe.com. Follow her on Twitter @ndungca.