Given the task definition and input, reply with output. This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

While there is some international commonality in the way political parties are recognized, and in how they operate, there are often many differences, and some are significant. Many political parties have an ideological core, but some do not, and many represent very different ideologies than they did when first founded. In democracies, political parties are elected by the electorate to run a government. Many countries have numerous powerful political parties, such as Germany and India and some nations have one-party systems, such as China. The United States is a two-party system, with its two most powerful parties being the Democratic Party and the Republican Party.
What are the two most powerful political parties in the United States?