With the window to gut a critical consumer protection regulation rapidly closing, the Treasury Department on Monday launched an unusual attack on the Consumer Financial Protection Bureau’s arbitration rule, relying heavily on a discredited industry theory that claims that trial lawyers routinely bully corporations into class-action settlements.

The Treasury released a 17-page report arguing that the rule, which would prohibit companies from sticking language into financial contracts that prevent consumers from pursuing class-action lawsuits, will “impose extraordinary costs” on businesses without providing benefits from an increase in industry compliance. Furthermore, the agency asserts that trial lawyers will enjoy a “large wealth transfer” if the rule is adopted.

A showdown could come to the Senate as early as Tuesday. Don Stewart, a spokesperson for Senate Majority Leader Mitch McConnell, R-Ky., said that a vote was possible this week, but had yet to be scheduled. Republicans need at least 50 votes for the resolution, but Republican Sens. Susan Collins, Lisa Murkowski, Lindsey Graham, John Kennedy, and Rob Portman have yet to commit; McConnell would need three of those five. He may also be able to pull in a Democratic vote in support.

Murkowski has told reporters she is leaning toward voting yes to overturn the rule. Lobbyists believe Collins, too, will vote yes, but Kennedy is a likely no vote. Graham is considered a hard no. Portman is publicly undecided, but Democrats are not counting on him.

The rule has gotten increased public attention after the Equifax breach, in which a forced arbitration clause played a role in stoking outrage at the company’s response. Corporations, meanwhile, have also banded together — you might call it a “class action” — to block the CFPB rule and prevent consumers from the class action option themselves.

The timing suggests the industry needs help in its bid to nullify the CFPB’s rule. A Congressional Review Act resolution that would do the trick with a simple majority vote has been stuck in the Senate, and under the rules, Congress has only until November 13 to pass it. Several Republicans have balked at killing the arbitration rule, which supporters contend will stop financial companies from ripping off their customers with impunity.

The Treasury deployed familiar arguments used by the industry and its mouthpieces. Claims that CFPB used misleading data and failed to recognize that consumers fare better in arbitration (which isn’t true) come directly from a Koch-funded Mercatus Center study, which the Treasury report cites.

But the Treasury’s biggest rhetorical weapon was a theory it called “blackmail settlements.”

“A long line of case law and legal literature acknowledges that defendants frequently settle class action suits for reasons unrelated to the merits of the class claims,” the report alleges. Because of the time and money that goes into defending these lawsuits, the Treasury says, attorneys can prove very effective in holding up companies. Though industry brought up this concern, CFPB did not properly take the costs into account, the Treasury claimed.

The blackmail settlement theory gained momentum in the 1990s, when conservative Judge Richard Posner laid it out in a class-action case called In re Rhone-Poulenc Rorer. Posner said that aggregating hundreds of lawsuits into a class-action against a medical device supplier would create “insurmountable pressure on defendants to settle,” denying class certification on those grounds. Since then, industry has consistently cited this to make themselves look like the henpecked victim of greedy trial lawyers.

But this theory is a myth. As a 2005 article in the Baylor Law Review explains, Posner didn’t rely on any evidence in making the blackmail claim. The company at issue never even raised pressure-to-settle as a defense. It just came out of Posner’s “statistical conjecturing” and “general distaste for the class-action device,” the authors say.

Judges have long had existing tools to throw out frivolous claims, and if they were truly inundated with such cases, they would put those tools to use. In its rulemaking, CFPB found that just 10 percent of the cases it studied led to summary judgments, where judges toss the cases for lacking merit. “If most class actions truly were devoid of any merit,” CFPB wrote, “the Bureau would have expected defendants to succeed more often in defeating such claims.”

The Treasury claimed summary judgments are tilted in favor of the plaintiffs and against corporations, which would be a rare feat in our current pro-corporate legal environment. Indeed, the courts have made it far harder to certify classes lately, not easier to facilitate trial lawyer shakedowns. What’s more, class-action suits are wildly expensive to bring and only payoff with a victory or a settlement, meaning that pursuing a frivolous claim would amount to an extraordinary risk with a firm’s own money. The more logical conclusion from the data is that class-action attorneys don’t spend huge amounts of time and effort trying to blackmail large corporations with meritless claims.

But this didn’t stop the Treasury from building a completely hypothetical chart (it’s literally labeled “hypothetical scenarios”) based on CFPB’s estimate of additional class-action suits if consumers aren’t forced into arbitration, claiming huge costs on businesses that outweigh benefits to society. It uses CFPB’s 10 percent figure of summary judgments as a proxy for meritless cases, neglecting that those cases were thrown out of court, and the plaintiffs never collected a penny on them.

Future cases expressly contradicted Posner, finding that the “blackmail settlement” thesis was a mere pretext to favor corporations. In Klay v. Humana, Judge Gerald Tjoflat wrote that if fears about legal exposure ruining an industry were justified, “the defendants can blame no one but themselves. … It would be unjust to allow corporations to engage in rampant and systemic wrongdoing, and then allow them to avoid a class action because the consequences of being held accountable for their misdeeds would be financially ruinous.”

This nails the primary point: Corporations don’t want protection from frivolous lawsuits but a blanket protection from lawsuits of any kind, regardless of the merits. They would rather steer consumer disputes away from the courts entirely and put them into an arbitration setting, where the deck is stacked against the ordinary person from gaining any restitution. The “blackmail” myth is a red herring, one that’s obvious from a moment’s scrutiny.

Whether the Treasury report will change matters in the Senate remains unclear; it is not typically a body swayed by reason when other means are available.

Ryan Grim contributed reporting. This story is being updated to reflect the unfolding vote count.

Top photo: Treasury Secretary Steven Mnuchin holds a news conference on Sept. 21, 2017 in New York City. Mnuchin discussed increased sanctions against the regime of North Korea.