Last year the vampires of finance bought themselves a Congress. I know it’s not nice to call them that, but I have my reasons, which I’ll explain in a bit. For now, however, let’s just note that these days Wall Street, which used to split its support between the parties, overwhelmingly favors the G.O.P. And the Republicans who came to power this year are returning the favor by trying to kill Dodd-Frank, the financial reform enacted in 2010.

And why must Dodd-Frank die? Because it’s working.

This statement may surprise progressives who believe that nothing significant has been done to rein in runaway bankers. And it’s true both that reform fell well short of what we really should have done and that it hasn’t yielded obvious, measurable triumphs like the gains in insurance thanks to Obamacare.

But Wall Street hates reform for a reason, and a closer look shows why.

For one thing, the Consumer Financial Protection Bureau — the brainchild of Senator Elizabeth Warren — is, by all accounts, having a major chilling effect on abusive lending practices. And early indications are that enhanced regulation of financial derivatives — which played a major role in the 2008 crisis — is having similar effects, increasing transparency and reducing the profits of middlemen.

What about the problem of financial industry structure, sometimes oversimplified with the phrase “too big to fail”? There, too, Dodd-Frank seems to be yielding real results, in fact, more than many supporters expected.