The second fight pits unilateralism against multilateralism—to what degree should the United States work through the channels of international law to effect foreign-policy goals?

While the conventional wisdom is that Republicans tend toward unilateralism and Democrats tend toward multilateralism, the reality is more complex. Both parties, especially once in power, have taken a pragmatic view of the benefits and drawbacks of multilateral institutions. It was under Democratic president Bill Clinton that the United States sidestepped the United Nations Security Council in mobilizing its NATO allies in 1999 to liberate Kosovo from Serbian aggression, and Republican president George W. Bush respected it enough to seek action under the existing Security Council resolutions to justify the 2003 U.S.-led invasion of Iraq,

The Republican Party is certainly home to plenty of unapologetic unilateralists, such as former U.S. ambassador John Bolton, but it also has its share of multilateralist voices as well, including Robert Zoellick, the former president of the World Bank, who could well become Secretary of State in a future Republican administration. It’s hard, despite his hawkish campaign-trail rhetoric, to imagine that a potential Mitt Romney administration would have leaned more toward Bolton than Zoellick.

As Republicans look to 2016, it seems likely, based on past anti-U.N. sentiment, that Paul will be among the most strident voices opposing U.N. influence. There’s really no basis to know where Christie or Rubio, who last month introduced a bill in the Senate tying U.S. funding for the United Nations to reform, will ultimately land in this debate—they could wind up closer to Paul or closer to multilateralists like Zoellick.