A key worry among American critics of NATO is that expanding the alliance into Eastern Europe may entangle the United States in conflicts that have little or no relevance to our genuine security needs.

But the 2011 NATO intervention in Libya is a reminder that even Washington's long-time allies like France and Britain can create the same danger. In their memoirs, Secretary of State Hillary Clinton and Secretary of Defense Robert M. Gates reveal (at times perhaps unintentionally) how those nations prodded the reluctant Obama administration into taking such a fateful step in Libya. Clinton herself was favorable to "humanitarian" military missions, while Gates was openly hostile, yet their accounts track closely, confirming how much of an impact allied lobbying had on American decision-making.