Senator Bernie Sanders has taken his public spat with Amazon.com Inc. (AMZN) to new heights.

On Wednesday, the Vermont independent and 2020 presidential contender introduced a bill that proposes taxing big companies for the federal benefits their low-wage employees use to make ends meet. The Stop Bad Employers by Zeroing Out Subsidies, or Stop BEZOS, Act is a pointed attack on Amazon CEO Jeff Bezos and demands that large companies that employ at least 500,000 people foot the bill for food stamps, public housing, Medicaid and other federal assistance received by their workers.

Under the bill, the likes of Amazon and Walmart Inc. (WMT) will be ordered to pay back every dollar in aid their workers receive from the government.

"In other words, the taxpayers of this country would no longer be subsidizing the wealthiest people in this country who are paying their workers inadequate wages," Sanders said at a news conference announcing the bill, according to the The Washington Post. "Despite low unemployment, we end up having tens of millions of Americans working at wages that are just so low that they can't adequately take care of their families."

The proposed legislation was introduced shortly after Amazon became the second company in the U.S. to reach a $1 trillion market cap. Sanders, who over the past few months has criticized the gulf in wealth between the online retailer’s CEO Jeff Bezos and its warehouse workers, took to Twitter to speak out against Amazon crossing the threshold. (See also: Amazon Pops Then Drops From Trillion-Dollar Value.)

"Amazon is worth $1 TRILLION," Sanders tweeted Tuesday. "Thousands of Amazon workers have to rely on food stamps, Medicaid and public housing to survive. That is what a rigged economy looks like."

Last week, Amazon hit back at Sanders’s allegations, claiming that his calculations are “inaccurate and misleading” because they factor in temporary and part-time workers. (See also: Amazon, Tesla Among the Most Dangerous for Workers.)

Bill Could Backfire, Warn Economists

Some economists questioned whether the "Stop BEZOS Act" will have the desired effect, noting that it could encourage large companies to avoid hiring workers deemed likely to collect federal benefits.

I'm afraid this is a solution that vilifies benefit recipients," said Jared Bernstein, a senior fellow at the Center on Budget and Policy Priorities and former economic adviser to Vice President Joseph Biden, according to Vox. "It's not hard to imagine that employers would be wary of hiring someone who they think — rightly or wrongly — would invoke the tax."