Wal Mart: If you can't beat 'em, join 'em.

In a major break with most other large companies, Wal-Mart Stores Inc. Tuesday told the White House that it supports requiring employers to provide health insurance to workers, a centerpiece of President Barack Obama's effort to provide near-universal coverage to Americans.

The support of Wal-Mart, the nation's largest private employer, could give momentum to one of the most-contentious aspects of legislation taking shape in Congress to fix the health system. To help pay for covering the 46 million uninsured, lawmakers have proposed mandating that all but small employers provide insurance for workers or help pay for it.

Lobbies for large corporations have opposed the idea. The U.S. Chamber of Commerce has fought such a mandate, saying it would prompt companies to cut jobs, lower wages and possibly drive them out of business. Wal-Mart -- which provides insurance to employees and wants to level the playing field with companies that don't -- on Tuesday delivered a letter to President Obama taking a different stance.

"We are for an employer mandate which is fair and broad in its coverage," said the letter, signed by Wal-Mart Chief Executive Mike Duke. Andrew Stern, president of the Service Employees International Union, also signed the letter, along with John Podesta, who led President Obama's transition team and is chief executive of the Center for American Progress, a liberal-leaning think tank.