James Madison had included provisions for equality in admittance of the new States in the first draft of the Constitution:
"If admission be consented to, new states shall be admitted on the same terms with the original states."
In spite of the Oct. 10, 1780, promises of the federal Congress and conditions of several State deeds of cession, a faction lead by Governor Morris of New York and Elbridge Gerry of Massachusetts advocated plans to limit the number of new states so that they would never outnumber the older states or to admit new states on a less than equal basis. Madison insisted that "the Western States neither would nor ought to submit to a union which degraded them from an equal rank with the other States." (2 Madison, "Journal of the Debates in the Convention which Framed the Constitution," 274 - Hunt's ed. 1908.)
George Mason stated:
"If the Western States are to be admitted to the Union, they must be treated as equals and subject to no degrading discrimination. They will have the same pride and other passions which we have, and will either not unite with or will speedily revolt from the Union, if they are not in all respects placed on an equal footing with their bretheren." (Clarence B. Carson, A Basic History of the United States, Volume 2, American Textbook Committee, c1995.)
A compromise resulted in the neutral statement in the Constitution:
"New states may be admitted by Congress into this union; but 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."
The principle of "equal footing" was later summarized by Justice Lurton in Coyle v. Smith, 221 U.S. 559 (1911):
"The power of Congress in respect to the admission of new states is found in the 3d section of the 4th article of the Constitution. That provision is that, 'new states may be admitted by the Congress into this Union.' The only expressed restriction upon this power is that no new state shall be formed within the jurisdiction of any other state, nor by the junction of two or more states, or parts of states, without the consent of such states, as well as of the Congress.
"But what is this power? It is not to admit political organizations which are less or greater, or different in dignity or power, from those political entities which constitute the Union. It is, as strongly put by counsel, a 'power to admit states.'
"The definition of 'a state' is found in the powers possessed by the original states which adopted the Constitution,-a definition emphasized by the terms employed in all subsequent acts of Congress admitting new states into the Union. The first two states admitted into the Union were the states of Vermont and Kentucky, one as of March 4, 1791, and the other as of June 1, 1792. No terms or conditions were exacted from either. Each act declares that the state is admitted 'as a new and entire member of the United States of America.' 1 Stat. at L. 191, 189, chaps. 7, 4. Emphatic and significant as is the phrase admitted as 'an entire member,' even stronger was the declaration upon the admission in 1796 of Tennessee [1 Stat. at L. 491, chap. 47] as the third new state, it being declared to be 'one of the United States of America,' 'on an equal footing with the original states in all respects whatsoever,'- phraseology which has ever since been substantially followed in admission acts, concluding with the Oklahoma act, which declares that Oklahoma shall be admitted 'on an equal footing with the original states.'
"The power is to admit 'new states into this Union.'
'This Union' was and is a union of states, equal in power, dignity, and authority, each competent to exert that residuum of sovereignty not delegated to the United States by the Constitution itself.To maintain otherwise would be to say that the Union, through the power of Congress to admit new states, might come to be a union of states unequal in power, as including states whose powers were restricted only by the Constitution, with others whose powers had been further restricted by an act of Congress accepted as a condition of admission. Thus it would result, first, that the powers of Congress would not be defined by the Constitution alone, but in respect to new states, enlarged or restricted by the conditions imposed upon new states by its own legislation admitting them into the Union; and, second, that such new states might not exercise all of the powers which had not been delegated by the Constitution, but only such as had not been further bargained away as conditions of admission.
"The argument that Congress derives from the duty of 'guaranteeing to each state in this Union a republican form of government,' power to impose restrictions upon a new state which deprive it of equality with other members of the Union, has no merit. It may imply the duty of such new state to provide itself with such state government, and impose upon Congress the duty of seeing that such form is not changed to one anti-republican,-Minor v. Happersett, 21 Wall. 162, 174, 22 L. ed. 627, 630,-but it obviously does not confer power to admit a new state which shall be any less a state than those which compose the Union."
Boyd v. State of Nebraska, 143 U.S. 135 (1892):
"Admission on an equal footing with the original states, in all respects whatever, involves equality of constitutional right and power, which cannot thereafterwards be controlled, and it also involves the adoption as citizens of the United States of those whom congress makes members of the political community, and who are recognized as such in the formation of the new state with the consent of congress."
As established by Justice Field in Escanaba & L. M. Transp. Co. v. City of Chicago (1882) 107 U.S. 678, 2 Sup. Ct. 185, regardless of prior territorial provisions, such as the Northwest Ordinance of 1787, the new States:
'[But the states] have full power to regulate within their limits matters of internal police, including in that general designation whatever will promote the peace, comfort, convenience, and prosperity of their people.'
Stated Justice Field in Illinois Cent. R. Co. v. State of Illinois, 146 U.S. 387 (1892):
"The state of Illinois was admitted into the Union in 1818 on an equal footing with the original states, in all respects. Such was one of the conditions of the cession from Virginia of the territory notrhwest of the Ohio river, out of which the state was formed. But the equality prescribed would have existed if it had not been thus stipulated. There can be no distinction between the several states of the Union in the character of the jurisdiction, sovereignty, and dominion which they may possess and exercise over persons and subjects within their respective limits..."
Factors that effect "equal footing" can be roughly separated into those pertaining to the "imperium" (political sovereignty, police powers, jurisdiction over citizens and others) of the State and the "dominium" (property, eminent domain or territorial jurisdiction) of the State:
The effects of Enabling Acts, terms and conditions of statehood, Congressional acts applicable to territorial government, etc. upon the subsequent political sovereignty and eminent domain of the State, (including "police" or "municipal" powers such as hunting regulations.)
Devolution of the Crown's title and trust over "Royal Rivers" or the "Sea and it's Arms" from the federal government to the sovereign people of the States, including offshore limits, beds and banks of navigable streams and common or public fishery.
Federal retention of title as proprietor of the "Public Lands" ceded by the original States lying within the new States east of the Mississippi as trustee for the purposes of disposal for payment of the war debt.
Federal retention of the "public domain" lands west of the Mississippi.
------------------->To State Navigable Waters
----------------> To "public Lands" Section
----> To Exclusive Federal Jurisdiction