Sen. Elizabeth Warren (D-Mass.) has been the public face of the Democratic Party’s feud with President Barack Obama over his trade agenda. But behind the scenes, Sen. Sherrod Brown (D-Ohio) quietly united his party behind a strategy that resulted in a major defeat Tuesday for the president.

Brown’s weeks of work came to fruition when Democrats voted to block legislation that would have given Obama so-called fast-track trade authority. Fast-track authority would strip Congress of the ability to amend trade deals negotiated by the president and is essential for the passage of Obama’s Trans-Pacific Partnership, a trade deal the administration is negotiating with 11 Pacific nations.