Non-defense discretionary spending. God, what a hideous term. The tip of the tongue takes a trip of ten steps and falls on its face at the -ding. In fact, it's such a revolting sequence of consonants, maybe that explains why politicians think we can cut it to the bone without anybody noticing.
Here is the case for noticing.
When government talks about spending as "investments," they're talking about this category, mostly. NNDS is everything that isn't Medicare, Medicaid, Social Security, defense, and mandatory spending on programs like unemployment benefits. It's everything that is infrastructure, education, training, disaster relief, environmental protections, international affairs, scientific research, and employee salaries.
In other words, it is the bulk of what we have historically called "Government." And in both President Obama and Rep. Paul Ryan's budgets, "Government" gets cut to a historic low as a share of, well, government. Here's the graph of non-defense discretionary spending ("Government") since 1970. After 2013, Obama's budget traces the orange line and Ryan's budget traces the blue line.
In the last half-century, the U.S. government has gradually changed from an investment engine to an insurance company. In 1969, direct payments to individuals and investments (i.e.: education and training, scientific research, and infrastructure) each made up one-third of the federal budget, Ron Brownstein reported. In the last half-century, wars have ended (the defense budget includes investment, too), and infrastructure has languished, while entitlements have grown. Now payments to individuals have doubled their share of the budget to 65 percent. Investments have fallen to 14 percent.