A proposed tax on high-cost, or “Cadillac,” health insurance plans has touched off a fierce clash between the Senate and the House as they wrestle over how to pay for legislation that would provide health benefits to millions of uninsured Americans.

 

Supporters, including many senators, say that the tax is essential to tamping down medical spending and that over 10 years it would generate more than $200 billion, nearly a fourth of what is needed to pay for the legislation.

Critics, including House members and labor unions, say the tax would quickly spiral out of control and hit middle-class workers, people more closely associated with minivans than Cadillacs.