United States President Barack Obama, a member of the Democratic Party, was endorsed or supported by some members of the Republican Party and by some political figures holding conservative views in the 2008 election. Although the vast majority of Obama's support came from liberal constituencies, some conservatives identified in him shared priorities or other positive attributes. As in any election, voters can and sometimes do cross party lines to vote for the other party's nominee. Republican and conservative Obama supporters were often referred to as "Obama Republicans", "Obamacans" or "Obamacons".

Andrew J. Bacevich Jr. is an American historian specializing in international relations, security studies, American foreign policy, and American diplomatic and military history. He is a Professor Emeritus of International Relations and History at the Boston University Frederick S. Pardee School of Global Studies. He is also a retired career officer in the Armor Branch of the United States Army, retiring with the rank of colonel. He is a former director of Boston University's Center for International Relations, now part of the Pardee School of Global Studies. Bacevich is the co-founder and president of the Quincy Institute for Responsible Statecraft.