When it comes to an approach to the outside world, the Republican Party would seem to be tearing itself apart. There are not one or two factions but several, all vying for a mandate from the party faithful. This is all happening while the Democrats appear more or less to be united -- if not always enthusiastic -- behind President Barack Obama's foreign policy, especially after the triumph of his interim deal with Iran.

In recent decades, the Republicans have usually been the more nationalist of the two major parties. Whereas Democratic foreign policy experts have been more at home among global elites, and more enthusiastic about pursuing altruistic humanitarian goals, Republican experts have been less comfortable at conferences abroad, and more concerned about the safety of the American homeland and its traditional allies than about trying to improve the lot of the rest of the world. As one might expect, defense budgets have usually fared better under Republican than Democratic presidents.

The problem for Republicans is that there are various kinds of nationalism. There is, for instance, the aggressive Dick Cheney and Donald Rumsfeld brand of nationalism, in which you proactively seek out enemies and destroy them, with relatively little concern for what the outside world thinks. Especially in a post-9/11 world, you can't take chances! This is a nationalism in which high defense budgets are encouraged, even as humanitarianism is de-emphasized. It is not that such nationalists are necessarily hardhearted. Rather, it is that they genuinely feel the world overall will be a more humane place with preponderant American power.

To one side of these Republican nationalists are Republican isolationists. Now isolationists are nationalists, too. They also believe that the most important thing in the world is a safe and secure American homeland. It is just that they feel this can be better achieved by staying out of foreign wars and other such entanglements, particularly in the Eastern Hemisphere. In their minds, American human and material treasure is simply too precious to be wasted abroad. Tried-and-true isolationists are actually rare in the Republican Party: just because you are against this or that military intervention certainly does not make you an isolationist. Rather, there are isolationist-trending Republicans of varying degrees who seek to do the minimum abroad, while concentrating on protecting and improving the homeland. They seek a perfectionism within the American continent only, with some concern for contiguous parts of the Western Hemisphere as well. The world overseas will just have to fend for itself.

To the other side of Republican nationalists are Republican neoconservatives. They combine a militant nationalism with Wilsonianism. Wilsonianism, named after Democratic President Woodrow Wilson, seeks an activist role in the world in order to spread American values of democracy and human rights. Whereas isolationists see America as mainly an example to the rest of the world, neoconservatives seek to use America as a launching pad to forcibly spread that example to other shores. To those of an isolationist bent, the military is for defending the homeland against a direct and credible attack. To Republican neoconservatives (as well as to liberal interventionists in the Democratic Party), the military is there to put distant and troubled societies to rights. For America can only be secure when the rest of the world, too, enjoys freedom. When traditional Republican nationalists bonded with neoconservatives, the result in the early years of the 21st century was the Iraq War, which isolationist-trending Republicans, as well as many others in both parties, now view as a disaster.

This rift sometimes defines how history is seen. Take the media, for example. Markedly influenced by liberal and neoconservative elites, the media has been generally averse to isolationism in all its forms and degrees. Thus, the great early and mid-20th century Republican, Robert Taft -- who opposed involvement in World War II -- is often held out for ridicule. While Taft was clearly wrong to oppose America's entry into the war when he did, it is important to realize that Taft's very caution in international affairs remains a mainstay both within the Republican Party and within the American heartland.