The correct answer to this open question is the following.
The Preamble can be used to evaluate how the federal government is doing its job in that the Preamble of the United States Constitution clearly and succinctly states the standard that the federal government needs to show and perform to govern the country. The Preamble clearly states that the government must maintain the union, establish justice, promote peace and welfare, and promote the liberties of the citizens. So that is the reference and the standard the US officials must follow to perform their jobs. This is a great responsibility.