Steven Saenz, who is Hispanic, graduated from college in the teeth of the recession, and went to architecture school in part to avoid entering the weak labor market. Even so, it took him nine months after completing his degree to find a job, and two more years to feel stable.

Now, however, Mr. Saenz has a good job at a Dallas architecture firm, and last year bought his first home with his wife. Still, Mr. Saenz, 32, said he and his wife watched their spending closely.

“Just being a product of graduating in the recession, I tend to focus more on saving,” he said.

Tax Support Stalls

Ever since they passed their $1.5 trillion tax-cut bill in December, Republicans have predicted that voters would come to love it. They were buoyed in February when, according to a previous survey, the law briefly earned the support of a majority of Americans. But the surge in support has stalled, and the law now evenly divides Americans, with 48 percent in favor and 47 percent opposed. There is no sign in the polling that the law will help Republicans court independent voters, who oppose the law by 54 percent to 40 percent, in the fall.

But the law appears to have helped Republicans’ election prospects in one important way: It appears to have made Republican voters feel better about the economy.

The share of Americans who say they and their families are better off financially than they were a year ago has jumped since December, to 36 percent from 29 percent. That jump is almost entirely concentrated among Republicans, and it coincides with the signing of the tax cuts. The improved sentiment could give Republican voters a reason to turn out in November — to reward the lawmakers they see as having given them a financial lift.

“It’s clear that the tax bill did have a significant impact on Republican confidence,” said Laura Wronski, a research scientist at SurveyMonkey.

Nancy Steele, a retired psychologist near Allentown, Pa., said she saw more cynical motives in the tax bill.