For more than a decade, Democratic leaders have pledged to eliminate a loophole that lets Wall Street executives pay a lower tax rate on their income than everyone else. The so-called carried interest loophole has been slammed by former vice president Joe Biden. Even President Donald Trump has pretended he wants to do away with it.

And yet, Democratic legislation to call Trump’s bluff and fix the problem is bottled up in the powerful tax-writing committee chaired by US representative Richard Neal — a Massachusetts Democrat who once helped lead the effort to eliminate the loophole but who has lately been raking in campaign cash from finance industry donors that have lobbied to preserve it.

Neal’s Wall Street donors have an interest in helping him defeat progressive Holyoke mayor Alex Morse in this Tuesday’s Massachusetts congressional primary: If Neal loses reelection, the next Ways and Means Committee chair could be representative Lloyd Doggett (D-Texas), who has been a vocal critic of the finance industry and the carried interest loophole.