I don't believe any serious political leader would eliminate Social Security. For all its challenges, the Program has made an important contribution in reducing the incidence of poverty among older Americans.
The Program faces big challenges on account of the nation's demographics (increasing share of the population comprised by people eligible for Social Security coupled with a lengthening life span of people eligible for Social Security meaning more people receive Social Security for a longer period). Determining how to fully fund the Program's anticipated payouts is a relatively straightforward actuarial exercise. Modest reforms can address Social Security's actuarial imbalances.
The health-related programs continue to drive the largest part of the nation's imbalances. Perhaps the leading challenge involved is finding an effective approach to slow the growth in medical expenditures, something that was largely outside the scope of the Affordable Care Act for which the primary goal was expanded health coverage, though CBO estimates some measure of savings albeit far short of what would be needed to eliminate the nation's long-term health-related imbalances. Medical expenditures cannot continue to grow at a multiple of the economy indefinitely, as foreign creditors won't be willing to pick up a growing share of those costs via financing U.S. deficits without the nation's debt stabilizing and then falling as a share of GDP over the longer-term. Numerous factors including debt-related risks, the need to tap savings countries such as Japan (aging + own debt challenges), and opportunities to earn attractive returns from growing economies outside the U.S., among other factors, could temper the flow of such funds to the U.S. in medium- and longer-term.
Until the issue concerning rapid growth in medical expenditures in the U.S. is resolved--and it's highly complex--public and private health care policies will either become more expensive (premiums/other costs rising faster than incomes grow), offer less coverage (procedures, pharmaceutical products, and/or technologies), and/or run imbalances. The challenge involved extends beyond Medicare/Medicaid Program design. A disproportionate share of medical cost increases also arise from hospital care, not physician appointments or medical supplies. The growing utilization and high cost of long-term care (e.g., at nursing homes) is also an emerging factor and has implications for Medicaid. These challenges need to be addressed comprehensively and objectively.