"No matter who we elect to Congress and as President, they are still stuck with some realities. There's a long historical perspective pdf file up at OMB, and the following figures are taken from tables 8.3 and 8.4, whch are on pages 140 and 141.

Since 1962, national defense spending has shrunk from 9.3% of GDP to 4%. Entitlement spending grew from 5.8% of GDP in 1962 to 11.2% in 2007. It's going to continue to grow rapidly for several decades, too.

As a percentage of the total federal budget, national defense spending went from 49.6% in 1962 to 20.1 in 2007. Entitlement programs went from 31% in 1962 to 56.2% in 2007." -- MaxedOutMama