U.S. state

In the , a  is a constituent political entity, of which there are currently 50.

Bound together in a political union, each holds governmental jurisdiction over a separate and defined geographic territory where it shares its sovereignty with the federal government.

Due to this shared sovereignty, Americans are citizens both of the federal republic and of the in which they reside.

citizenship and residency are flexible, and no 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).

governments are allocated power by the people (of each respective ) through their individual constitutions.

All are grounded in republican principles, and each provides for a , consisting of three branches, each with separate and independent powers: executive, legislative, and judicial.

States are divided into counties or -equivalents, which may be assigned some local governmental authority but are not sovereign.

or -equivalent structure varies widely by , and states also create other local governments.

States, unlike U.S. territories, possess a number of powers and rights under the  Constitution.

States and their citizens are represented in the  Congress, a bicameral legislature consisting of the Senate and the House of Representatives.

Each is also entitled to select a number of electors (equal to the total number of representatives and senators from that ) to vote in the Electoral College, the body that directly elects the president of the United States.

Additionally, each has the opportunity to ratify constitutional amendments, and, with the consent of Congress, two or more states may enter into  compacts with one another.

The police power of each 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, , and federal elections have generally been considered primarily 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 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 and the rights of individuals.

The Constitution grants to Congress the authority to admit new states into the Union.

Since the establishment of the in 1776 by Thirteen Colonies, the number of states has expanded from the original 13 to 50.

Each new has been admitted on an equal footing with the existing states.

The Constitution is silent on the of whether states have the power to secede from the UnionShortly after the Civil War, the U.S. Supreme Court, in  v. White, held that a cannot unilaterally do so.