WASHINGTON, D.C.: The Senate unanimously approved legislation Tuesday that should make it easier for millions of Americans to keep their health coverage when they change jobs. Also included is an amendment forcing insurers to cover mental illness just as they do physical ailments. Sponsored by Senators Nancy Kassebaum and Edward Kennedy, the bipartisan bill guarantees that people who are covered by insurance through a current employer will not lose coverage when moving to a new employer's health plan, regardless of any pre- exisiting medical conditions. The bill is now headed to House-Senate conference. House Republicans have included in their version a provision to allow people to choose tax-exempt medical savings accounts, but President Clinton promised to veto such a bill, saying healthy people would drop insurance coverage and drive up insurance costs for others. TIME White House correspondent James Carney reports that the veto threat assures that MSA's will not be included in the conference report. Carney calls the legislation important, but adds: "It is reform at the margins. It's a small bill, but extremely popular with Republicans because it's a way of saying 'We got you health care with little cost to the federal government.' The problem is that real health care reform will not have been done. This does not deal with the spiraling costs of Medicare and Medicaid, or the nearly 40 million Americans who are already uninsured." Carney says that in political terms, the bill is a "win-win" situation. Republicans, eager to show that Congress can be effective when they're in power, can go on the campaign trail and contrast their reform to the failed complex and costly plan devised by Hillary Clinton in 1994. But President Clinton has supported the Kennedy- Kassebaum bill from its inception, and will likely argue that an extreme Republican Congress has passed far too little moderate legislation.