Board member Robert E. Primus said on LinkedIn that he received an email from the White House Wednesday night terminating the position he has held since he was appointed by Trump in his first term. The vacancy would allow Trump to appoint two additional Republicans to the board before its decision on the Union Pacific-Norfolk Southern merger though the Senate would have to confirm them.

Primus was the only board member to oppose Canadian Pacific’s acquisition of Kansas City Southern railroad when it was approved two years ago because he was concerned it would hurt competition. He was named Board chairman last year by former President Joe Biden and led the board until Trump, after his election, elevated Board member Patrick Fuchs to Chairman.

This follows Trump’s previous firings of board members at the National Transportation Safety Board, Federal Reserve, Equal Employment Opportunity Commission and Nuclear Regulatory Commission, which are all supposed to be independent agencies.

“Robert Primus did not align with the President’s America First agenda, and was terminated from his position by the White House,” White House spokesman Kush Desai said. “The administration intends to nominate new, more qualified members to the Surface Transportation Board in short order.”

Primus said he doesn’t think the firing is valid because the White House didn’t offer any cause for it, and he plans to fight. He also rejected their explanation for the move because he has long tried to encourage railroads to serve every industry better and help them grow, but he has already been removed from the STB website.

“I’ve been pro growth across the board in terms of encouraging growth in the freight rail network, which in turn will grow our national economy. So if that’s not being in line with America first, then I don’t know what America he’s saying is first,” Primus said to The Associated Press.

He said the firings at all these agencies threaten their independence and credibility. Primus said in his tenure the STB always strove to be impartial and apolitical.

Democratic U.S. Sen. Tammy Baldwin, who serves on the Commerce Committee, said it’s clear that “Donald Trump is trying to stack the deck so the federal government rubberstamps the merger as a huge favor for Wall Street and wealthy railroad owners.” She said Primus has been a fair regulator who worked hard to make sure railroads delivered for their customers and focused on safety.

Every rail worker union and the nonprofit Rail Passengers Association also quickly condemned the firing.

“The explanation provided for this decision — that his position has been “eliminated” — is nothing short of outrageous. Appointed bodies established through federal code are not designed to be erased at the whim of powerful corporate interests,” said the SMART-TD union that represents concductors. “This action is unprecedented, unlawful in spirit, and reeks of direct interference from hedge funds and the nation’s largest rail carriers.”

The board is set to consider Union Pacific’s $85 billion acquisition of Norfolk Southern in the next two years before deciding whether to approve the nation’s first transcontinental railroad and reduce the number of major freight railroads in the U.S. to five.

Primus said the biggest problems in the industry are the lack of growth and poor service after all the deep cuts railroads have made over the last decade in the interest of efficiency and improving profitability. He hasn’t taken a position on the UP-NS deal, but he doesn’t think mergers will necessarily improve competition.

“We don’t need to merge to increase competition. We need to understand that we have to grow,” he said.