Various esteemed Democratic lawmakers, suddenly concerned about the consequences of their actions, write in the letter that new derivatives rules “will inevitably result in significant competitive disadvantages for U.S. firms operating globally.” Then comes the real howler, when the letter writers claim that “the proposals are inconsistent with Congressional intent.” As if any of these folks didn’t understand that they were transferring enormous discretion to regulators to reshape derivatives and other financial markets.

Apparently it’s now dawning on the New York Democrats that if U.S. financial houses are forced to demand lots of cash collateral from creditworthy derivatives customers overseas, but foreign banks aren’t, those customers will choose the cheaper alternative. Like Federal Reserve officials who have only recently highlighted flaws in clearinghouses mandated by the law, lawmakers who voted for Dodd-Frank are increasingly eager to criticize it now that it’s too late to make much difference.

Mr. Schumer’s whine in a meaningless letter is especially notable because he could have killed Dodd-Frank last summer. Passed after a close Senate cloture vote shortly before the August recess in an election year, the law would still be just a gleam in Barney Frank’s eye if Mr. Schumer had chosen to join the opposition.

We should also note that several Republicans who didn’t support Dodd-Frank—Representative Peter King and several House freshmen—also signed the letter urging regulatory restraint.

But with Mr. Schumer, who voted to inflict this burden on an economy still struggling with high unemployment and slow growth, this is an all-too familiar pattern of behavior that can be summarized as follows:

Step One: Vote for destructive law.

Step Two: Complain about said law, while doing nothing to repeal it.

Step Three: Raise campaign money by showing to business community the volume of said complaints.

It was almost easy to forget that Mr. Schumer helped enact the 2002 Sarbanes-Oxley financial accounting law when he spent much of the rest of the decade complaining about the stifling burden of financial regulations.

Looking forward, we can expect Mr. Schumer to express at myriad fundraising events his sympathy for those living with the consequences of Dodd-Frank. It’s a good bet that he’ll also claim that, if not for his valiant efforts on Capitol Hill, the financial reform would have been so much worse. And expect New York’s financial elite to keep writing checks.

There’s a word for people who keep falling for this: suckers.