Fast-forward to earlier this month, when Trump hastily announced he would be placing tariffs on steel and aluminum imports, a proposal deemed sacrilegious by traditional Republican orthodoxy and sure to win him few allies. One of them was Brown, who welcomed action he said could stop China from dumping steel into the U.S. market, calling it “well overdue.”

Such an alliance has incensed Republicans, even those closest to Trump, who are concerned the tariff push will undermine the benefits they hope to reap from a good economy and new tax cuts while boosting rivals they need to defeat in November. Other manufacturing-state Democrats like Bob Casey of Pennsylvania and Joe Manchin of West Virginia, applauded Trump’s move. And Democrat Conor Lamb, who is proving to be competitive in next week’s special election in a Trump district outside of Pittsburgh, also backed the proposal — even using it to outflank his opponent, Rick Saccone, who also supports tariffs…

Brown has long been a critic of free-trade agreements, opposing NAFTA since its inception when he was a congressman. He is in frequent contact with Trump’s top trade negotiator, Robert Lighthizer. And while the Democratic base demands party lawmakers defy Trump at every turn, Brown sees his stance on trade as central to his own identity. Railing against China and currency manipulation was a centerpiece of his 2012 re-election campaign, for example.