I laugh how foreigners never understand the dynamics of our two party system. They don't understand that the Democrats aren't liberal and Republicans are not conservative. They are coalitions on political ideology which could only exist in a system like the US.
The democrats aren't about socialism or entitlements, they are about representing the democratic interpretation of the US constitution. They are the federalists and the voice of the people crossing state lines. Those include the combined voices of many disenfranchised groups and minorities within smaller areas who don't have much representation locally. They have to balance their favored constitutionally granted powers of the federal government with the power of the individual constituencies granted by the constitution.
The republicans aren't about big business or impeding civil progress, they are representing the republican interpretation of the US constitution. They are "States Rights" activists and the voice of the majority of each region from which they come. These include a minority view in the national scale of rural and some suburban areas in a country where urban areas are the population, financial, and power centers. They have to balance their favored constitutional limitations with the power of the federalist and national nature of the constitution.
The system isn't parliamentary, its congressional in the real sense of the word. Each population zone sends its equal representative to the House of Representatives, and each geographical state sends two senators no matter the population to the Senate. The Governor doesn't just govern down, along with the senators they govern up by influencing the federal executive bureaucracy.
More often than in parliamentary systems, you'll see people from different parties in a geographical region will be more similar to each other on individual issues than their own party peers. The caucus, while similar to a parliament's distributional nature, has little power over final votes or what comes out of a legislative committee. The nature of campaign finance and elections in the U.S. prevents parties from choosing the final viable candidates - while one may get party endorsement, to get on a ballot requires a lot of support in each locality, though this changes depending on each state's rules.
America Legislators and Presidents in action aren't like the traditional parliamentary conservatism, liberalism, socialism, and corporatism (whatever they name their parties in ech country). They are a collection of ideas and perspectives from all over a very large, diverse confederated nation under a larger federal government.
But what do I know, I'm an ignorant American, who considers a High School Band trip to the CN Tower foreign policy experience.
I would cite regulation, but I know you will simply ignore it.
