What general trends are found in U.S. defense spending in the last half-century? How has defense spending become entangled with ideological disputes?

What will be an ideal response?

An ideal response will:
1, Explain that defense spending was high during the Cold War and has generally decreased since then, with a few upward trends during the Vietnam War, the Reagan rearmament, and since the September 11, 2001, terrorist attacks.
2, Indicate that liberals argue that money spent on defense is money taken away from social needs such as health and education. Thus, the decrease in military spending at the end of the Cold War was a "peace dividend" to be used for important social programs.
3, Discuss how conservatives advocate increases in defense spending to keep America safe.