In Defense of Multi-Decade budget planning horizons

Earlier today Matt Yglesias tweeted this:

"Ryan specifics aside, the DC wonk fetish for multi-decade budget planning horizons is inherently ridiculous."

This is something he has discussed before. Broadly his point is that if we enacted the Ryan budget there is nothing preventing politicians 10 years from now from restoring medicare commitments to what they are currently.

This is true, but I think it misses a larger issue that there is a strong status quo bias in the American political system, and large changes usually persist for many decades. If the Bush tax cuts werent expiring it is hard to imagine Obama making the case to raise tax levels for those making over 250k. Medicare and Medicaid persist. So does social security. Government makes commitments, citizens plan around those commitments, those commitments become popular. This creates a path dependency that makes large changes in government commitments semi-permanent.

I do think that large cuts to medicare now would be important in 30 years. And for Ryan, reducing medicare funding would change the 30 year fiscal outlook.