Last month Democrats on the Senate banking committee passed a reasonably tough financial regulatory reform bill. Now Republican leaders have suddenly begun lashing out against it.

Did they belatedly discover some problem? No. They suddenly realized that their bet that reform would be watered down as it moved along might not pan out.

Their battle cry of “no more bailouts” is disingenuous. They are not worried that reform will make bankers’ lives too easy, they are worried that it will make them too hard.

The Republicans started loudly objecting only after Senator Blanche Lincoln, an Arkansas Democrat who is chairwoman of the agriculture committee, took an unexpectedly strong stand in favor of reining in financial derivatives, the complex and largely unregulated instruments that were at the heart of the financial crisis. (Her committee has jurisdiction, because derivatives have long been used to trade commodities.)