State citizenship and residency are flexible, and no government approval is required to move between states, except for persons restricted by certain types of court orders (such as paroled convicts and children of divorced spouses who are sharing custody).
All are grounded in republican principles, and each provides for a government, consisting of three branches, each with separate and independent powers: executive, legislative, and judicial.
States are divided into counties or county-equivalents, which may be assigned some local governmental authority but are not sovereign.
States, unlike U.S. territories, possess a number of powers and rights under the United States Constitution.
Each state is also entitled to select a number of electors (equal to the total number of representatives and senators from that state) to vote in the Electoral College, the body that directly elects the president of the United States.
The police power of each state is also recognized.
Historically, the tasks of local law enforcement, public education, public health, regulating intrastate commerce, and local transportation and infrastructure, as well as, local, state, and federal elections have generally been considered primarily state responsibilities, although all of these now have significant federal funding and regulation as well.
Over time, the Constitution has been amended, and the interpretation and application of its provisions have changed.
The general tendency has been toward centralization and incorporation, with the federal government playing a much larger role than it once did.
There is a continuing debate over states’ rights, which concerns the extent and nature of the states’ powers and sovereignty in relation to the federal government and the rights of individuals.
The Constitution grants to Congress the authority to admit new states into the Union.
Since the establishment of the United States in 1776 by Thirteen Colonies, the number of states has expanded from the original 13 to 50.
Each new state has been admitted on an equal footing with the existing states.
The Constitution is silent on the question of whether states have the power to secede from the UnionShortly after the Civil War, the U.S. Supreme Court, in Texas v. White, held that a state cannot unilaterally do so.