Barney Frank blames crypto panic for his bank’s collapse. Elizabeth Warren blames Trump.

Former Rep. Barney Frank and Sen. Elizabeth Warren — two key architects of the post-2008 system of Wall Street regulation — are at odds over what’s dragging down banks once again.

Frank, who chaired the House Financial Services Committee in the wake of the global financial crisis and wrote sweeping new rules enacted in 2010, most recently served on the board of New York’s Signature Bank, which regulators shut down Sunday.

From his front-row seat, he blames Signature’s failure on a panic that began with last year’s cryptocurrency collapse — his bank...