Those credit union trade groups hailed the Senate vote.

"The CFPB's rule encourages credit union members to act against their own best-interest by engaging in costly class action litigation which depletes the resources of the membership as a whole and instead benefits trial lawyers most," said CUNA  President/CEO Jim Nussle. "This rule was just the latest example of the one-size-fits-all rulemaking coming from the CFPB and thankfully Congress acted to remedy the situation."

"While NAFCU strongly supports consumer protections, credit unions should not have been included in this rulemaking as they are not the bad actors the rule is meant to target," said NACFU President/CEO B. Dan Berger. "Credit unions should also have access to various forms of dispute resolution, but this rule, as written, could have led to a rise in frivolous lawsuits."

But CFPB Director Richard Cordray called the Senate vote a mistake.

"It robs consumers of their most effective legal tool against corporate wrongdoing," he said. "As a result, companies like Wells Fargo and Equifax remain free to break the law without fear of legal blowback from their customers."

Sen. Elizabeth Warren (D-Mass.) agreed.

She said that Republicans "gave a giant wet kiss to Wall Street. No wonder Americans think the system is rigged against them. It is."

Still, studies show that few credit unions use mandatory arbitration clauses in their financial contracts.

A 2015 CFPB study of banks and credit unions showed that only 3.3% of the credit unions in the sample used arbitration clauses in their credit card contacts. And only 8.2% of the credit unions in the study used arbitration language in their checking account contracts.

The CFPB issued the rule in July. It immediately was criticized by the financial community as a costly and unnecessary regulation. And the Trump Administration said that the agency's study of the need for the rule was fatally flawed.

Republicans began pushing for the rule to be nullified under the Congressional Review Act, which allows Congress to rescind agency rules within 60 legislative days of it being issued.

The vote to nullify the rule was among the first victories Republicans have had in reining in the CFPB, which they consider a rogue, powerful agency with little oversight. It was created in Dodd-Frank and its director can only be removed for cause, although that is being challenged in federal court.

Senate Banking Chairman Mike Crapo (R-Id.) said the vote sent the agency an important message.

"Today's vote was an important step in asserting Congressional oversight of an agency that has routinely demonstrated a lack of accountability," Crapo said. "The CFPB's arbitration rule was based on a flawed study, which academics, Congress and federal financial regulators claimed could be harmful to consumers and the economy."

However, the Banking Committee's ranking Democrat, Sherrod Brown of Ohio sharply disagreed.

"Forced arbitration takes power away from ordinary people and gives it to big banks and Wall Street companies that already have an unfair advantage," Brown said. "By voting to take rights away from customers, the Senate voted tonight to side with Wells Fargo lobbyists over the people we serve."