Congress is capitalized because it refers to a specific institution, the U.S. Congress. The U.S. Congress is the legislative branch of the U.S. government and is composed of two houses: the House of Representatives and the Senate. It is a proper noun because it is a specific and unique entity.
Capitalizing Congress helps to distinguish it from other uses of the word “congress” that refer to different legislative bodies in other countries or contexts. By capitalizing Congress, it emphasizes that we are specifically referring to the legislative branch of the United States.
On the other hand, the term “U.S. government” or “federal government” is not capitalized because it is not a proper noun. The U.S. government is a broad term that encompasses various institutions, departments, and agencies. It is not a single, monolithic entity, but rather a complex system of governance.
While the U.S. Congress is part of the U.S. government, it is just one component among many. Therefore, it is more appropriate to capitalize Congress as a proper noun, but not the U.S. government as a whole.
It is worth noting that the rules of capitalization can vary depending on the style guide being followed. However, in general, the capitalization of Congress as a proper noun is widely accepted and used in formal writing.