(CNN) Sen. Bernie Sanders will join progressive groups in Iowa, Wisconsin and Michigan next week as part of a nationwide campaign to drum up grassroots opposition against the new Republican-backed tax law ahead of the midterm elections.

The Vermont independent will take direct aim at Trump-era Republicans' signature legislative achievement in those three key states, two of which, Michigan and Wisconsin, were instrumental in the President's 2016 victory over Hillary Clinton.

Sanders, who already announced plans to stump for Pete D'Alessandro, a 2016 aide now running for Congress, on February 23 in Des Moines, Iowa, is scheduled to headline an event in Cedar Rapids that evening, before leading rallies the next two days in Green Bay, Wisconsin, and Lansing, Michigan. He will also host a rally for Democrat Randy Bryce, who is running in Wisconsin's first congressional district, home to House Speaker Paul Ryan, during his time in the state.

The tax law has seen an uptick in popularity since it was passed by Republicans in the House and Senate and signed by President Donald Trump in December. According to a Monmouth University poll released in January, 44% of Americans approve of the plan and 44% disapprove of it.

In a statement, Sanders ripped the tax bill, calling it "one of the worst pieces of legislation in the modern history of our country."

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