Final answer:
Alexander's beliefs on gay marriage and trade suggest a mix of social liberalism and selective economic cooperation, not aligning perfectly with traditional political categories.
Step-by-step explanation:
The question regarding Alexander's beliefs can be situated in the realm of political philosophy and public policy, which falls under Social Studies. Alexander supports gay marriage and believes the US should trade only with countries that also support gay marriage. Typically, supporting gay marriage is associated with more liberal or progressive ideologies. However, the belief in restricting trade to countries that support gay marriage adds an element of economic policy that's not typically aligned with a singular political ideology. The question doesn't fit neatly into established categories such as Liberal, Conservative, Libertarian, or Isolationist; instead, it reflects nuanced personal beliefs that combine social liberalism with some form of selective economic cooperation.