American presidential elections often provide a forum to air differences on military strength between the opposing candidates and their parties. This was particularly true after Vietnam, when a clear distinction between the Republican and Democratic approaches to defense took shape. The GOP favored robust military spending, took a hard line toward the Soviet Union, was skeptical of international organizations and placed less stress on treaties to promote American security. Democrats, by contrast, emphasized international organizations, diplomacy and the promotion of collective and humanitarian interests. By the 1980s, the Republican notion clearly resonated more deeply with the American public: Ronald Reagan and many other Republicans successfully won votes by portraying their Democratic opponents as soft on defense.
In the 1990s, the distinction between the parties on defense issues blurred as Bill Clinton and other Democratic leaders came to recognize the price their party had paid for being considered weak on national security. While the size of the U.S. military declined with the end of the Cold War, the Clinton administration’s approach to military cuts was not significantly different from plans developed by George H.W. Bush's secretary of defense, Dick Cheney. Clinton and congressional Democrats supported robust funding of the smaller military and proved willing to use it in the Balkans and against Saddam Hussein's Iraq.
Many Democrats were critical of George W. Bush's invasion of Iraq in 2003, but most backed the post-Sept. 11 military buildup. Having learned from Clinton's success, Barack Obama, during his 2008 bid for the White House, was critical of U.S. involvement in Iraq but supportive of military strength in general including an expanded counterinsurgency effort in Afghanistan. While different in tone, there was much similarity between the defense policy proposals of John McCain and Obama in 2008, and of Mitt Romney and Obama in 2012.