§7. The first clause of the next section provides, that "new states may be admitted into this union," and requires the consent of congress and of the states concerned, to the formation of new states from old ones. A provision of this kind was deemed necessary in view of the large extent of vacant lands within the United States, and of the inconvenient size of some of the states then existing. The territory north-west of the Ohio river had been ceded to the general government by the states claiming the same; and a territorial government had already been established therein by the celebrated ordinance of 1787. From this territory have since been formed and admitted, the states of Ohio, Indiana, Illinois, Michigan and Wisconsin. §8. South of the Ohio river also was a large tract, principally unsettled, within the chartered limits of Virginia, North Carolina and Georgia, extending west to the Mississippi river, from which, it was presumed, new states would be formed. Justice, however, to these states, as well as to others in all future time, required the general provision above mentioned, that "no state should be divided without the consent of its legislature and of congress." §9. The next clause authorizes congress "to dispose of and make all needful rules and regulations respecting the territory and other property of the United States." If the general government has power to acquire territory, it must have the right to exercise authority over it. This express grant establishes beyond doubt a power which had been questioned under the confederation. In pursuance of the power here granted, congress has made rules and regulations for governing the people of different portions of such territory previously to their admission as states into the union. §10. The next section declares, that "the United States shall guaranty to every state in this union a republican form of government; and shall protect each of them against invasion, and on the application of the legislature, or of the executive (when the legislature cannot be convened,) against domestic violence." Art. 4, sec. 4. The propriety of a power to prevent a state from changing its government to any other than a republican form, is evident. It is equally proper that a state, when invaded by a foreign enemy, or in case of an insurrection within its own borders, should have protection and aid from the general government; especially as the states have surrendered to it the right to keep troops or ships of war in time of peace. (Art. 1, sec. 10.) Chapter XLV. Provision for Amendments; Assumption of Public Debts; Supremacy of the Constitution, &c.; Oaths and Tests; Ratification of the Constitution.