Profitable Giants Like Amazon Pay $0 in Corporate Taxes. Some Voters Are Sick of It.

Amy Klobuchar, the Minnesota senator who is also running, has taken a different approach. She has tied a proposed increase in the corporate tax rate, to 25 percent from the current 21 percent, to plans to rebuild bridges, roads and airports. About $400 billion of her trillion-dollar infrastructure plan would be financed by the tax increase.

Former Vice President Joseph R. Biden Jr., who officially entered the race on Thursday, has not issued a formal proposal on corporate taxes. In remarks last May, however, he blamed a “yawning” income gap for tearing the country apart. “We have to deal with this tax code,” he said. “It’s wildly skewed toward taking care of those at the very top.”

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In surveys, more Americans support raising the corporate tax rate than lowering it or leaving it unchanged. And several Democratic candidates, like the former housing secretary Julián Castro, invoke “fair share” rhetoric in speeches or vow to undo the recent Republican tax law. Others, like Senator Kamala Harris of California, have focused more on the individual income tax and reducing the burden on working families.

But raising the headline tax rate on corporations won’t eliminate the corporate zero-rate club, which also results from companies taking advantage of loopholes and the way global profits are taxed.

Even before the last Republican tax overhaul, there was an effort in both parties to lower the top 35 percent corporate tax rate in order to better compete with other countries trying to lure businesses to their shores. Mr. Obama proposed a top rate of 28 percent, with a further discount for domestic manufacturers. These efforts generally coupled a lower tax rate with a tightening of loopholes, however.

Republicans in 2017 pushed down the corporate rate to 21 percent, in addition to expanding some generous tax breaks. The new law allowed immediate expensing of capital expenditures, for example, in order to goose investment. That was one of the primary reasons that so many more corporations paid fewer taxes, according to the institute’s report.

Mr. Trump and his Republican allies argued that the tax changes would stimulate investment, job growth and global competitiveness. That year, he appeared at a rally in working-class Youngstown, the seat of Mahoning County, and delivered a message full of economic reassurance.