The state consent requirement in Article IV, Section 3 mandates that state legislatures must approve before their territory is used to form new states. The provision states: ''No new State shall be formed or erected within the Jurisdiction of any other State; nor any State be formed by the Junction of two or more States, or Parts of States, without the Consent of the Legislatures of the States concerned as well as of the Congress.'' This double-lock mechanism—requiring both state legislative consent and congressional approval—prevents the federal government from unilaterally redrawing state boundaries or breaking apart existing states. The Framers included this protection because four states (Connecticut, Georgia, North Carolina, and Virginia) still held claims to western territories at the time of the Constitutional Convention and demanded veto authority over those lands becoming separate states. Historical applications include Virginia consenting to Kentucky (1792) and West Virginia (1863), North Carolina to Tennessee (1796), and Massachusetts to Maine (1820). The requirement preserves state sovereignty over territorial integrity while giving Congress authority to admit new states when proper consent is obtained.