Yet many Americans are just taking stock of the transformations wrought by global trade. In two dozen conversations with voters across the country, only two said they had heard of the proposed new trade deal, the Trans-Pacific Partnership, involving the United States and a host of Pacific Rim nations.

Instead, the concerns they expressed were about changes in their own lives and communities over the last couple of decades.

“When we first did that big trade agreement I thought it was a good idea, but now I’m getting a little more conservative about it,” said Phyllis Arthur, a 74-year-old Republican from Walnut Creek, Calif. “I think we’re being overwhelmed by the goods coming in. That’s practically all that’s available in the stores.”

Kevin White, a 47-year-old Democrat from Dayton, Ohio, said it was hard to find a job. He used to work at a hospital; now he gets federal disability payments.

“The jobs went overseas,” lamented Mr. White. “Then people couldn’t afford their mortgages and we had a crash and nobody was able to buy anything.”