Congress moved to kill an Obama-era rule that would make it easier for states to launch retirement programs for millions of workers who do not have plans through their jobs.

The Senate narrowly approved, 50 to 49, a resolution to eliminate a rule that would have removed regulatory hurdles for states creating the programs. The vote broke down mostly along party lines, with the exception of Republican Sens. Bob Corker (Tenn.) and Todd C. Young (Ind.), who voted against the resolution.

The resolution now heads to President Trump’s desk.

The vote creates uncertainty for the seven states that have passed laws to create a retirement program. The states — California, Oregon, Illinois, Maryland, Connecticut, New Jersey and Washington — could face confusion over which regulations they would be subject to.

The programs would generally work by automatically enrolling employees who don’t have plans through their jobs, including many small business workers and part-timers, into individual retirement accounts. Those employees would have the contributions taken straight from their paychecks. People who do not want to participate would be able to opt out.

About 55 million Americans don’t have a simple way to save for retirement through work, according to AARP.

The resolution eliminates a Labor Department rule finalized last year, which clarified that states would not have to comply with the strict rules and reporting requirements governing employer-based retirement plans and pensions. Those regulations could lead to additional paperwork and higher compliance costs.

But the accounts have been strongly criticized by business groups and Republicans who say states should not be running retirement plans. The U.S. Chamber of Commerce and the Investment Company Institute, a financial trade group, are among those who called on Congress to eliminate the rule. “The Senate has taken a positive step to ensure that savers in state-run retirement plans have the same strong consumer protections that workers with private-sector employer retirement plans have relied on for more than four decades,” said ICI President Paul Schott Stevens.

Some lawmakers defending the plans said they were surprised to see strong Republican opposition over an approach that has had bipartisan support. Sen. Chris Van Hollen (D-Md.) pointed out Wednesday that the bill authorizing Maryland’s retirement program was signed into law by Republican Gov. Larry Hogan. And in March, Utah’s Republican Treasurer David Damschen sent a letter to Sen. Orrin G. Hatch (R-Utah), asking him to vote against the resolution.

Corker was the lone Republican to vote against a similar resolution in March affecting city plans, but this time he was joined by Young, who said in a statement after the vote that he thinks the state plans can help people struggling to save for retirement. “It is clear our current retirement system is based on an outdated model,” he said. “While state-based retirement plans are not my first choice, if implemented carefully, they could help close the retirement savings gap.”

The loss of the labor rule could cause delays in two dozen states considering their own programs, Democrats and consumer advocates say. “This will have a significant chilling effect across our retirement system,” said Sen. Patty Murray (D-Wash.) on the Senate floor Wednesday. “It would send the political message that Congress is opposed to state flexibility to increase retirement savings.”

Some of the states launching retirement plans, including Oregon and California, are planning to move forward with the programs even if the rule is overturned. California, for example, hired an executive director for its retirement plan earlier this year and expects to have the program running by early 2019. Oregon is on pace to launch its state-run plan this summer.

On Wednesday evening, Sen. Martin Heinrich (D-N.M.) and Sen. Chris Murphy (D-Conn.) introduced a bill that could provide some clarity for the cities and states seeking to launch retirement plans. The bill, which was co-sponsored by Murray, would amend the Employee Retirement Income Security Act, the law governing workplace retirement accounts, to state that it does not apply to IRAs launched by states and cities.

While savers can open individual retirement accounts on their own, research shows that workers are much more likely to save for retirement if they can do it easily through their jobs. A report released last month by the Center for Retirement Research at Boston College found that most of the people using IRAs already have access to a retirement account.

The majority of money flowing into IRAs came from people who were transferring money over from a workplace retirement account, such as a 401(k). The researchers concluded, however, that automatically enrolling workers into IRAs would be a way to increase participation from people who aren’t already saving for retirement.

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