Sen. Joe Manchin, the West Virginia Democrat famous for his vow to maintain the Senate filibuster and thereby scuttle much of President Biden’s agenda, recently published an op-ed opposing the For the People Act, Democrats’ whopping voting-rights bill. That article strongly echoed talking points from the U.S. Chamber of Commerce — and appeared shortly after the influential pro-business lobby resumed donations to Manchin’s campaign after nearly a decade.

“The timing of Sen. Manchin’s announcement is highly suspicious,” Kyle Herrig, president of the progressive government watchdog group Accountable.US, said in a statement to Salon. “Not long after the Chamber reopened their corporate checkbook for him, he made his opposition to voting rights known. Now millions of Americans may face significant roadblocks when they try to exercise their constitutional right to vote. Once again the U.S. Chamber of Commerce has found a way to stop any progress on voting rights from progressing on Capitol Hill.”

Accountable.US has launched a six-figure “Drop the Chamber” campaign challenging corporations like Microsoft, Target and Salesforce to back up their public support of voting rights by cutting ties with the group, accusing it of “siding against millions of Americans who will be subject to these racist voter suppression laws.”

“It’s on Chamber members that claim to support voting rights to end their relationships and speak out against this assault on Americans’ rights to vote,” Herrig said, “because anything less makes them complicit.”