Since Congress will never reduce benefits to retirees, the only way to make the trends sustainable is by raising taxes significantly.

What this illustrates is an important difference between economists and others on the Budget. To some non-economists, we can solve the Budget problems by reducing "spending" without touching entitlements. Economists--or anyone else who has mastered arithmetic and understands the categories in the Budget--know that the only items that really matter are Social Security and Medicare. Primarily the latter.