WASHINGTON—While a major change in position, Wal-Mart Stores Inc.'s endorsement last week of an employer health care coverage mandate is unlikely to have much effect on whether federal lawmakers include a mandate as part of reform legislation, lobbyists and others say.

In a letter to President Obama, Wal-Mart President and Chief Executive Officer Mike Duke wrote that the huge retailer is for an employer mandate that “is fair and broad in its coverage.”

“Not every business can make the same contribution, but everyone must make some contribution,” Mr. Duke wrote in the letter also signed by Andrew Stern, president of the Service Employees International Union, and John Podesta, a former chief of staff to President Clinton and now president and CEO of the Washington think tank Center for American Progress.

Legislation updated

Wal-Mart's endorsement of an employer mandate came just days before the Senate Health, Education and Labor Committee released a new version of health care reform legislation that fills in the details of an employer mandate. Those details were not included in the first version of the legislation proposed by panel Chairman Sen. Edward Kennedy, D-Mass., and Sen. Chris Dodd, D-Conn. At the time, committee leaders said the details were being discussed.

In the latest version, which the panel is scheduled to consider this week, all but the smallest employers would be required to offer health care coverage and pay 60% of the premium or be slapped with an annual assessment of $750 for each full-time employee and $375 for each part-time employee. Employers with 25 and fewer employees would be exempt from the so-called play-or-pay assessment.

Until recently, the idea that Bentonville, Ark.-based Wal-Mart, the nation's largest private employer, with 1.4 million employees, would endorse an employer mandate would have been considered unlikely at best.

Wal-Mart itself was the target of AFL-CIO-supported legislation that would have required employers to spend a certain percentage of payroll on health care or pay the difference to state programs providing coverage to the uninsured. The bills were written in such a way as to apply only to Wal-Mart.

That drive came to an end after a district court in 2006 and a federal appeals court panel in 2007 ruled that such measures ran afoul of a provision in the Employee Retirement Income Security Act that preempts state and local laws and regulations that relate to employee benefit plans.

Becoming involved

While those anti-Wal-Mart measures failed, being the target of negative publicity was not pleasant for the company.

“We came under a lot of scrutiny. Some people thought we weren't doing a particularly good job,” Linda Dillman, Wal-Mart's executive vp-benefits and risk management in Bentonville, said earlier this year at a meeting of the National Business Group on Health in Washington.

Since then, Wal-Mart has improved its health care benefits programs, with 5.5% of its employees now lacking health insurance, down from nearly 10% in 2007.

Wal-Mart also decided to get actively involved in trying to shape health care reform legislation.

“If you don't participate in the discussion, you won't like the outcome,” Ms. Dillman said.

While Wal-Mart is making its views known in a high-profile way, its support of an employer mandate will not be critical in swaying legislators or other employers, observers say.

“It will have zero impact. It is just one episode in the debate and is out of step with everyone else in the business community,” said Neil Trautwein, vp and employee benefits counsel for the National Retail Federation in Washington, which opposes a mandate.

“I don't think this changes anything and just shows there is a difference of opinion on the issue among employers,” said Chantel Sheaks, a principal with Buck Consultants L.L.C. in Washington.