That changed in 1803 with the Louisiana purchase. Since most of the Founders were still around then and didn’t complain about it then I have to assume they were OK with the government owning it.
Professor Natelson disagrees with you.
He is one of America’s premier constitutional lawyers and scholars and an originalist. Here is a list of some of his publications.
CONSTITUTIONAL PUBLICATIONS
Now Available For Download Free: A Treatise on the Law of Amendment Conventions: State Initiation of Constitutional Amendments: A Guide for Lawyers and Legislative Drafters (2014)
New article: Does The Freedom of the Press Include a Right to Anonymity? The Original Understanding, 9 N.Y.U. J. of Law & Liberty (forthcoming, 2015)
* On the Constitution in General:
The Original Constitution: What It Actually Said and Meant (Tenth Amendment Center, 2010) (2nd ed., 2011) (book).
The Fiduciary Foundations of Federal Equal Protection (with Gary Lawson & Guy Seidman), 94 B.U. L. Rev. (forthcoming, 2014)
The Founders Hermeneutic: The Real Original Understanding of Original Intent, 68 Ohio St. L.J. 1239 (2007).
The Constitution and the Public Trust, 52 Buff. L. Rev. 1077 (2004).
A Reminder: The Constitutional Values of Sympathy and Independence, 91 Ky. L. J. 353 (2003).
The Constitutional Contributions of John Dickinson, 108 Penn. State L. Rev. 415 (2003).
* On Amending the Constitution:
State Initiation of Constitutional Amendments: A Guide for Lawyers and Legislative Drafters (2014)
Founding-Era Conventions and the Meaning of the Constitutions Convention for Proposing Amendments, 65 Fla. L. Rev. 615 (2013)
The Article V Convention Process and the Restoration of Federalism, 36 Harvard J. L. & Pub. Pol. 955 (2013)
Proposing Constitutional Amendments By a Convention of the States: A Handbook for State Lawmakers (2d ed., 2013)
James Madison and the Constitutions Convention for Proposing Amendments, in Union and States Rights: A History and Interpretation of Interposition, Nullification, and Secession 150 Years After Sumter (Neil H. Cogan ed., 2013) (book)
Proposing Constitutional Amendments by Convention: Rules Governing the Process, 78 Tenn. L. Rev. 693 ( 2011)
The State-Application-and-Convention Method of Amending the Constitution: The Founding-Era Vision, 28 Cooley L. Rev. 9 (2011)
Amending the Constitution by Convention: Practical Guidance for Citizens and Policymakers (Independence Institute, 2012) (updated and amended version of an earlier paper published by the Goldwater Institute)
Amending The Constitution by Convention: Lessons for Today from the Constitutions First Century (Independence Institute, 2011) (updated and amended version of an earlier paper published by the Goldwater Institute)
Amending the Constitution by Convention: A More Complete View of the Founders Plan (Independence Institute, 2010) (updated and amended version of an earlier paper published by the Goldwater Institute)
* On Congressional Power Commerce and Necessary & Proper Clauses:
The Origins of the Necessary and Proper Clause (with Lawson, Miller & Seidman) (Cambridge University Press 2010) (book).
Health Laws of Every Description: John Marshalls Ruling on a Federal Health Care Law, 12 Engage, No. 1 (June, 2011) (with Dave Kopel)
Commerce in the Commerce Clause: A Response to Jack Balkin, 109 Mich. L. Rev. First Impressions 55 (2010) (with Dave Kopel).
Tempering the Commerce Power, 68 Mont. L. Rev. 95 (2007).
The Legal Meaning of Commerce In the Commerce Clause, 80 St. Johns L. Rev. 789 (2006).
The Agency Law Origins of the Necessary and Proper Clause, 55 Case W. Res. L. Rev. 243 (2004).
* On Congressional Power Taxing and Spending:
Judicial Review of Special Interest Spending: The General Welfare Clause and the Fiduciary Law of the Founders, 11 Tex. Rev. L. & Pol. 239 (2007).
The General Welfare Clause and the Public Trust: An Essay in Original Understanding, 52 U. Kan. L. Rev. 1 (2003).
* On Congressional Power Campaign Finance:
The Original Scope of the Congressional Power to Regulate Elections, 13 U. Pa. J. Const. L. 1 (2010).
* On Congressional Power Money:
Paper Money and the Original Understanding of the Coinage Clause, 31 Harvard J.L. & Pub. Policy 1017 (2008).
* On Congressional Power Indian Affairs:
The Original Meaning of the Indian Commerce Clause, 85 Denv. U. L. Rev. 201 (2007).
* On Congressional Power Federal Land:
Federal Land Retention and the Constitutions Property Clause: The Original Understanding, 76 U. Colo. L. Rev. 327 (2005).
More in Chapter 6, pp. 106-110, The Original Constitution: What It Actually Said and Meant
* More on Congressional Power: Chapters 5 & 6, The Original Constitution: What It Actually Said and Meant
* On the Executive PowerRecess Appointments:
The Origins and Meaning of Vacancies that May Happen During the Recess in the Constitutions Recess Appointments Clause , 37 Harvard J. of L. & Pub. Poly 199 (2014)
* On the Executive Power and Impeachment:
The Original Meaning of the Constitutions Executive Vesting Clause Evidence from Eighteenth-Century Drafting Practice, 31 Whittier L. Rev. 1 (2009).
More in Chapters 7 & 11, The Original Constitution: What It Actually Said and Meant
* On The States & Republican Government:
The Original Meaning of the Privileges and Immunities Clause, 43 Ga. L. Rev. 1117 (2009).
The Guarantee Clause, in The Heritage Guide to the Constitution (2005).
Initiative and Referendum and the Republican Form of Government, in The Battle over Citizen Lawmaking (Carolina Ac. Press 2000).
The Enumerated Powers of States, 3 Nev. L. J. 469 (2003).
Statutory Retroactivity: The Founders View, 39 Idaho L. Rev. 489 (2003).
A Republic, Not a Democracy? Initiative, Referendum, and the Constitutions Guarantee Clause, 80 Tex. L. Rev. 807 (2002).
More in Chapters 3 & 6, The Original Constitution: What It Actually Said and Meant
* First Amendment:
Does The Freedom of the Press Include a Right to Anonymity? The Original Understanding, 9 N.Y.U. J. of Law & Liberty (forthcoming, 2015)
The Original Meaning of the Establishment Clause, 14 Wm. & Mary Bill Rights J. 73 (2005).
More in Chapter 9, The Original Constitution: What It Actually Said and Meant
* Fifth Amendment:
Statutory Retroactivity: The Founders View, 39 Idaho L. Rev. 489 (2003).
More in Chapter 9, The Original Constitution: What It Actually Said and Meant
* Ninth and Tenth Amendments:
The Enumerated Powers of States, 3 Nev. L. J. 469 (2003).
More in Chapter 10, The Original Constitution: What It Actually Said and Meant
* State Constitutions:
No Armed Bodies of MenMontanans Forgotten Constitutional Right, 63 Mont. L. Rev. 1 (2002).
Blocking the Cure for Columbine: Implications of State Constitutional Cartelization (Independence Institute, 1999).
LEGAL HISTORY PUBLICATIONS (OTHER THAN CONSTITUTIONAL HISTORY)
Magna Carta, entry for the Encyclopedia of the Supreme Court of the United States (Macmillan Reference [Gale-Cengage] 2008).
Corpus Juris Civilisan Internet Compilation of Classical Roman Law Sources, (2002-03).
The Government as Fiduciary: Lessons from the Reign of the Emperor Trajan, 35 Richmond L. Rev. 191 (2001).
Montana Estates in Land Statutes: History and Commentary (Univ. of Mont. 1991).
Running with the Land in Montana, 51 Mont. L. Rev. 17 (1990).
Comments on the Historiography of Condominium: The Myth of Roman Origin, 12 Okla. City L. Rev. 17 (1986) (digested and reprinted in 4 Common Ground (Sept., Nov. 1988)).
PUBLIC POLICY PUBLICATIONS
State Fiscal Policy and Economic Growth in the Rocky Mountain West (Independence Institute, 1998).
Tax and Spending Limits for Montana? Criteria for Assessing Current Proposals (Independence Institute, 1994).
Peyote, Multiculturalism and the Caricature of the West, 52 Mont. L. Rev. 453 (1991).
REMEDIES PUBLICATIONS
Montana Remedies Law (course book, 1988).
Mending the Social Compact: Expectancy Damages for Common Property Defects, 66 Or. L. Rev. 109 (1987).
REAL PROPERTY PUBLICATIONS
Lateral and Subjacent Support, in Powell on Real Property (Matthew Bender 2001).
Conveyances of Real Property Not By Deed, in Powell on Real Property (Matthew Bender 1999).
Boundaries, in Powell on Real Property (Matthew Bender 1998).
Condominiums, Reform, and the Unit Ownership Act, 58 Mont. L. Rev. 495 (1997).
Modern Law of Deeds to Real Property (Aspen Law & Bus. Supp. 1997).
Modern Law of Deeds to Real Property (Little, Brown Supp. 1996).
Modern Law of Deeds to Real Property (Little, Brown Supp. 1995).
Modern Law of Deeds to Real Property (Little, Brown Supp. 1994).
Modern Law of Deeds to Real Property (Little, Brown Supp. 1993).
Law of Property Owners Associations (Little, Brown Supp. 1991).
Montana Estates in Land Statutes: History and Commentary (Univ. of Mont. 1991).
Consent, Coercion, and Reasonableness in Private Law: The Special Case of the Property Owners Association, 51 Ohio St. L.J. 41 (1990).
Law of Property Owners Associations (Little, Brown Supp. 1990).
Running with the Land in Montana, 51 Mont. L. Rev. 17 (1990).
Law of Property Owners Associations (Little, Brown Supp. 1989).
Mending the Social Compact: Expectancy Damages for Common Property Defects, 66 Or. L. Rev. 109 (1987).
Keeping Faith: Fiduciary Obligations in Property Owners Associations, 11 Vt. L. Rev. 421 (1986).
Buyer Brokerage: Does It Still Exist After Velten v. Robertson?, 55 U. Colo. L. Rev. 83 (1983).
Modern Law of Deeds to Real Property (Little, Brown 1992) (606 pp.).
Law of Property Owners Associations (Little, Brown 1989) (749 pp.).
Real Property (course book, 1991, 1995, 1997, 2001).
How to Buy and Sell a Condominium (Simon & Schuster 1981) (popular trade paper back).
Real Estate Law Columnist, Denver Rocky Mountain News (1982-84).
OTHER PUBLICATIONS
Literally hundreds of other op-eds, CLE materials, and short articles since 1967 on various subjects, including law, policy, and real estate.