Beri Fox, president and chief executive of Marble King in Paden City, W.Va., possibly the last American manufacturer of toy marbles, said she had not yet focused on the candidates’ overall plans, just “bits and pieces.”

Making sure American companies can compete with China is a priority for her, said Ms. Fox, who employs 28 people. She hopes that Mr. Trump’s confrontational approach on trade will work in the long run, but also feels that Mr. Biden cares deeply about domestic manufacturers. She has not decided whom to support for president.

For some, the battle for the Democratic nomination is still mostly background noise.

With so many candidates still in contention, “it just doesn’t seem worth my time to pick a heartthrob at this time,” said Rick Woldenberg, chief executive of Learning Resources in Vernon Hills, Ill., a family-owned manufacturer of educational materials and toys.

Mr. Woldenberg’s primary concern is the future of his business, which employs more than 200 people. The 2017 tax cuts engineered by Mr. Trump and his party helped generate more cash for investment, he said, but tariffs on imports have been punishing, raising the cost of materials and straining relations with customers and international vendors.

He also finds the president’s routine combativeness unsettling, not to mention his impeachment.

“I tend to favor politicians who are more moderate in their views,” Mr. Woldenberg said. “And I would not consider Trump to be especially moderate.”

Yet neither are Mr. Sanders and Ms. Warren, he said. Labeling them “very extreme,” he said that expensive plans like Medicare for all would depress the economy and that a wealth tax would be “catastrophic.”

The generally positive economic outlook, of course, could shift significantly in the coming year. The recent flare-up in tensions between the United States and Iran was a reminder that by the time of the election, international events could eclipse domestic ones.