President Clinton went on record last month opposing Medical Savings Accounts, which would give senior citizens a chance to spend tax-free money on health care, including dental care. MSAs are part of the Republican proposal to overhaul Medicare. Seniors would get a specific amount of money each year from the government to buy health-insurance policies and pay for medical care not covered by the plan. But Clinton said MSAs wouldn`t work. In a recent speech, he said it would lead to the healthiest and wealthiest seniors taking money out of the program, leaving the sicker and poorer patients in Medicare. "If enough of this happened, it literally could cause the Medicare program to wither on the vine."