Democratic lawmakers went into their bailout negotiations with Treasury Secretary Henry Paulson with some promising approaches for restraining executive pay.

We don’t yet know what happened inside those negotiations, aside from a bit of reported shouting. But we do know what came out: a bailout that does precious little to limit the outrageously extravagant pay rewards that give top executives the incentive to behave outrageously.

Members of Congress who back the bailout, you may have noticed, have been singing a different tune. Rep. Barney Frank, a lead negotiator on the bailout bill, has even hailed the legislation’s executive pay provisions as the first “restrictions on excessive CEO compensation” in U.S. history.

The bailout bill’s one-page summary delivers the same celebratory message. The title for the summary’s section on CEO pay: “No Windfalls for Executives.”

The bailout now blessed by both the Senate and the House does, to be sure, include some long-overdue reforms on executive pay. The legislation has a ban on “golden parachutes,” for instance, and language that lets the feds “claw back” executive earnings based on phony accounting.

And the legislation also includes a provision that places a $500,000 cap on the individual executive pay that bailed-out companies can deduct from their taxes. Any executive pay over that cap — including pay in the form of stock options and other so-called “performance-based incentives” — will now be taxed.

This represents a solid advance over current law. Our current $1 million deductibility cap on executive pay only applies to straight salary. Companies can deduct everything else, no matter how many millions that everything else ends up totaling.

All these executive pay restrictions in the bailout bill, listed like this, certainly do sound impressive. So what’s the problem? Just this: Nearly every executive pay restriction in the bailout bill comes with a built-in loophole.

Take, for instance, that $500,000 cap on how much executive pay bailed-out companies can deduct off their taxes. This cap only applies when the Treasury Department buys up over $300 million of a company’s “troubled assets” through an auction process. If Treasury Secretary Paulson’s people buy up a company’s troubled assets directly, the $500,000 deductibility cap doesn’t apply. Nor does the “clawback” provision.

Even the bailout bill’s celebrated ban on golden parachutes comes with a loophole. The golden parachute ban, in auction bailout situations, only applies to executives hired after the auction takes place. Those executives who led their companies into the bailout zone will be able to ride off, into the sunset, with saddlebags stuffed with windfalls.

But that’s not the worst of it. In situations that don’t involve auctions, the bailout legislation directs the Treasury secretary to “require that the financial institution meet appropriate standards for executive compensation.” Who will define “appropriate”? The legislation leaves that up to Secretary Paulson.