Writing in the July/August 2007 issue of Foreign Affairs, then-candidate Barack Obama outlined his foreign-policy views. He wrote that after the financial and human cost of the Iraq War, “many Americans may be tempted to turn inward and cede our leadership in world affairs. But this is a mistake we must not make. America cannot meet the threats of this century alone, and the world cannot meet them without America.”

He then harkened back to three Democratic presidents:

Such leadership demands that we retrieve a fundamental insight of Roosevelt, Truman, and Kennedy — one that is truer now than ever before: the

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