Final answer:
New states can be admitted to the United States by Congress, with certain conditions. Consent of the concerned state legislatures and Congress is required for the formation of new states.
Step-by-step explanation:
New states can be admitted to the United States by Congress. However, there are certain conditions that must be met. No new state can be formed within the territory of an existing state without the consent of both the concerned state legislature and Congress. Additionally, the junction of two or more states or parts of states to form a new state also requires the consent of the involved state legislatures and Congress. For example, West Virginia was admitted as a state during the Civil War because it did not secede along with the rest of Virginia. Virginia was not recognized as a state during that time, which allowed the admission of West Virginia.In summary, new states can be added to the United States through a process involving the consent of the concerned state legislatures and Congress.