GOP Reps. Michele Bachmann of Minnesota and Walter Jones of North Carolina released a letter signed by 22 House Republicans on Tuesday condemning fast-track authority as a measure that allows Obama to “unilaterally write legislation making the pacts’ terms U.S. federal law.” Rep. Darrell Issa of California, meanwhile, has complained about the Obama administration’s “secretive, closed-door negotiating process” on the deals that fast-track authority would prevent Congress from amending.

Outside Congress, tea party movement leaders are delivering a similar message. Judson Phillips, the head of Tea Party Nation, has railed against Obama’s trade agenda. So have Bruce Fein, an adviser to Sen. Rand Paul (R-Ky.), and Phyllis Schlafly, founder of the conservative advocacy group Eagle Forum.

If Obama has fast-track authority, “the House cedes to the president its constitutional power to write legislation that regulates commerce with foreign nations,” Schlafly said in a recent email to supporters. “We’ve never had a president who so arrogantly grabs and uses such unlawful power.”