“The slavish devotion to shareholders has gotten out of control,” he said.

The more aggressive efforts to regulate corporate behavior are among many leftward moves for Democrats on economic issues. They include an embrace of new taxes on the wealthy and a growing consensus that all Americans should at least have the option — if not be forced — to obtain affordable government-run health insurance.

With Mr. Trump’s $1.5 trillion tax cut, which took effect last year, already changing corporate behavior, Democrats are looking for ways to prod businesses to share more of the winnings with workers.

The tax cuts delivered windfalls, sometimes in the billions of dollars, to corporations by lowering their income tax rate to 21 percent from a previous high of 35 percent. Administration officials promised that the reduction would fuel investment, economic growth and wage gains, and it did, at least modestly, in the first year.

But one of the most noticeable effects of the law was a surge in buybacks, which neared $800 billion for the 2018 fiscal year for companies in the S&P 500, according to analysts at Goldman Sachs. For 2019, those companies will buy back nearly $900 billion in shares, Goldman projects, which would be nearly a third of all corporate cash spending. That would be up from a quarter in the 2017 fiscal year, renewing progressives’ desire to increase corporate regulation.

“That you can see the Trump tax cuts go straight into buybacks is both startling and offensive, given the levels of inequality that exist and the investments our country needs to be making,” said Mike Konczal, a senior fellow at the liberal Roosevelt Institute who has pushed Democrats to take aim at buybacks and pursue other ways to force companies to invest more in workers.