Senators Bernie Sanders (I-VT) and Elizabeth Warren (D-MA) sent a blistering letter to the head of President Donald Trump’s Labor Department this week, urging the agency to reconsider a pending rule that would give fiduciaries wide cover to offer riskier assets like Bitcoin and other cryptocurrencies in retirement plans.

The proposed rule, floated in March, would grant fiduciaries the immunity to offer volatile and opaque assets like crypto, private equity, and private credit in 401(k) plans—so long as they stipulate that they considered various factors before offering access.

“The proposed rule is harmful to American workers and counter to statute, Congressional intent, existing regulations, and case law,” Sanders…