Aging demographics are a big problem for the United States.

Spending on Medicare is one the biggest contributors to the US's over-spending problem.

Over the past several decades, the growth in spending for Medicare has far outpaced the growth in income that the US receives through taxation.

Specifically since 1971, US's income from taxes(bold black line) has 26X'd, but spending on Medicare has 190X'd.

Income from taxation is not growing fast enough to keep up with this level of spending.