When the White House announced its National Security Strategy last month, it titled it A Blueprint for Pursuing the World That We Seek. A better title might have been The Fun Is Definitely Over. The document used the phrase "hard choices" three times, called for "a disciplined approach to setting priorities" and predicted "trade-offs among competing programs and activities." The nature of those trade-offs was never spelled out, but the implication was clear: America doesn't have as much money and power as we once thought. We can no longer conduct foreign policy on a blank check.