While the largest categories of spending, such as entitlement programs or debt interest, do not offer lawmakers a lot of flexibility, as Visual Capitalist's Jeff Desjardins notes, the government does get to decide how discretionary spending – about $1.3 trillion in FY2019 – gets put to use.
DISCRETIONARY SPENDING OVER TIME Today's animation from data scientist Will Geary shows the evolution of US discretionary spending from 1963 until today: The US budget is generally divided into three main categories: Discretionary Spending: This category, depicted in the animation, is the optional part of the budgetary equation – it's the aspect that most people talk about, as the allocation of funding towards different things like defense, education, and transportation can be changed by lawmakers.
Meanwhile, in Fiscal Year 2019, the government has allocated $1.3 trillion (today's dollars) to the budget: Things haven't changed much since 1963 in that defense still comprises the majority of spending – in fact, the only recent time periods where US defense spending fell below 50% were roughly between 1977-1981 and 1999-2004.
American spending on defense dwarfs all other countries, but there are other categories that make up decent chunks of the discretionary budget as well.
While they seem small on the above chart, transportation (7%), education (7%), and veteran benefits (6%) are all actually categories that receive over $70 billion of annual funding – still a significant piece of change.