The banks have fought their war against financial reform on four fronts.

They have pushed for delays, lobbied allies in Congress to repeal aspects of Dodd-Frank, worked over regulators to make the rules as loose as possible and threatened legal challenges and filed lawsuits.

The battle has been overwhelming, with a scrappy band of pro-reform rebels outnumbered and overpowered by the empire’s resources. The public appears to be on the side of the insurgents, but perhaps can’t follow or understand debates about whether “swaps” — what are those? — should be “pushed out” or not — what’s that? (English translation below.)

During all of these fights, the banks have had a stalwart ally holding back greater reform: Establishment Democrats.

Such Democrats, the Robert E. Rubin wing of the Democratic Party, opposed moves to break up the big banks after the 2008 global crisis. These stalwarts prevented a reinstatement of the…