How Spain and France still shape American rights—if you know where to look
By a regulated optimist who grades in pencil, votes with both hands, and still believes maps should tell the truth.
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I. The country with two constitutions
Every legal system keeps a diary and a dream. Ours files the diary under "common law" and the dream under "the Constitution." But across the South and West there is a third ledger—stamped in Spanish and French—that still decides where streets run, how towns are laid out, who inherits, who owns the water, and how old promises become present duties. This isn't a romance; it's the operating system.
What follows is a field guide to the American civil-law half: the code in Louisiana, the land grants and town plans from the Laws of the Indies, the community-property regimes of the West, and the watery grammar—pueblo rights, acequias, and prior appropriation—where Iberian usage and frontier custom braided themselves into law.
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II. Louisiana: the mixed-jurisdiction that never stopped mixing
Louisiana is the American classroom where civil law seats itself next to common law and copies nothing. The line begins with A Digest of the Civil Laws now in Force in the Territory of Orleans (1808), drafted chiefly by Louis Moreau-Lislet and James Brown—our first American civil code—later reworked in 1825 and carried forward into the 1870 code we still cite. Scholars who read the 1808 text against its sources found heavy debts to Spanish authorities (not just French)—the Siete Partidas and related compilations—alongside the then-new Code Napoléon. Louisiana, in short, is not "Napoleonic" in the way bar trivia supposes; it is Iberian-French-American, in that order and in that proportion.
You can feel that civil-law DNA in living rules. Forced heirship—today narrowed but unmistakably alive in Civil Code art. 1493—reserves a piece of the estate for certain descendants, a civil-law brake on total testamentary freedom; it is a concept native to the French and Spanish tradition and an exotic in the common-law garden. The point is not quaintness; it is continuity.
Louisiana also keeps vocabulary that the rest of America visits only as a tourist: usufruct (use without full ownership), legitime (the forced portion), prescription (where others say "limitations"). If you want to understand how American pluralism works in practice, don't start in Washington; start in a Louisiana notarial office.
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III. Treaties that still breathe: Spanish grants and the Court that said "sí"
The most eloquent sentence the Supreme Court ever wrote in Spanish is invisible—because it is translated. In United States v. Percheman (1833), Chief Justice Marshall read the Adams–Onís Treaty to protect Spanish land grants in Florida, giving treaty text immediate domestic force. That decision remains the ur-case for honoring pre-annexation titles—treaty promises as enforceable property, not museum labels.
On the Pacific, the story was rougher. The California Land Act of 1851 forced holders of Spanish/Mexican grants to prove title before a federal commission or lose it to the public domain—a procedure that honored the treaty in theory and strained it in practice. The result was decades of litigation and partial confirmations that still lace county maps and family histories. California's own archives preserve the diseños—the hand-drawn maps that accompanied many claims—so you can watch a legal culture change ink mid-stroke.
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IV. The Laws of the Indies: town-making as public health and public morals
Long before zoning, the Spanish crown issued the Ordinances of 1573—the Laws of the Indies—with exacting rules for siting towns: where to place the plaza mayor, how to orient streets to winds and sun, which institutions front which sides of the square. Those instructions crossed with conquistadors and friars into what are now Santa Fe and San Antonio, leaving a physical jurisprudence you can still walk: plaza-first urbanism, civic and sacred buildings around the square, a grid that treats climate as law.
If you think design is policy, the Laws of the Indies read like a municipal code with a soul: air, shade, drainage, hierarchy—all written as if the town were a moral instrument.
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V. Marriage and money: the Spanish community that followed the couple West
Nine U.S. jurisdictions—AZ, CA, ID, LA, NV, NM, TX, WA, WI—live with community property, a civil-law regime rooted in Iberian rules for gananciales. The intuition is simple: marriage is an economic partnership; what flows in during the partnership belongs to the partnership. English common law rarely went there; Spanish law did. Statutes and state high-court opinions across the West acknowledge this lineage explicitly. In Texas, for example, the state's own historical encyclopedia identifies community property's Castilian origins.
The practical effect is not academic. In these states, business lawyers draft differently, courts divide differently, and households carry a quieter equality into their bookkeeping—one more Iberian current beneath the Anglo surface.
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VI. Water: the republic's other constitution
A polity is what it does with its thirst. In the Southwest, the Spanish-Pueblo acequia system—ditches governed by a mayordomo with duties allocated by turno—is not folklore but public law. New Mexico statutes recognize acequia associations as political subdivisions, with immunities and powers to manage diversions and oppose harmful transfers. The law's language—Spanish and specific—travels from statute book to headgate.
California carries two Iberian fingerprints in water. First, the courts have recognized pueblo water rights—a Spanish/Mexican doctrine giving a town priority to its native river water for municipal needs—most prominently litigated by Los Angeles into the 20th century. Second, the state embraced prior appropriation (first-in-time, first-in-right) during the Gold Rush in Irwin v. Phillips (1855), formalizing the miners' custom of diversion and use. The first doctrine descends from Spain; the second from frontier necessity—but both remind us that American water law is a composite art, not a single tradition.
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VII. What judges mean when they say "history and tradition"
Contemporary opinions lean on "history and tradition" to decide what counts as a right. But whose history? If the archive omits Spanish and French chapters, the jurisprudence will too. A court that sees only Blackstone will misread a state that also speaks Las Siete Partidas; a judge that remembers Jamestown and forgets Santa Fe will call some liberties "novel" that are, in fact, older—just catalogued in another language.
The fix is methodological: when rules turn on historical pedigree, courts must widen the bibliography. Louisiana's code, New Mexico's acequia statutes, California's pueblo cases, Florida's Spanish grants—these are not curios. They are precedent.
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VIII. The practical playbook (you can use this tomorrow)
1) Brief like a bilingual. If you practice in civil-law or former-Spanish territory, cite the Digest of 1808 when it illuminates a Louisiana provision; cite Percheman when a treaty promise supports a land claim; cite pueblo decisions (e.g., San Fernando) when a municipal right rests on Spanish law.
2) Teach like a cartographer. A 1L property course that includes the Laws of the Indies and community property will produce lawyers who can actually read the towns they live in.
3) Plan like a pragmatist. When cities write design standards for heat and flood today, they are reinventing the Indies—orientation, shade, drainage—as if it were new. It isn't. Use it without apology.
4) Govern like a neighbor. Fund acequias as infrastructure, not heritage; publish ditch schedules alongside reservoir ledgers. A republic that budgets for headgates is one that understands itself.
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IX. Three scenes
New Orleans, a notary's office.
A young lawyer explains forced heirship to an exasperated entrepreneur who wants to leave everything to a foundation. The code declines the offer, politely. The city outside continues to be itself.
Santa Fe, on the plaza at noon.
Tourists photograph the Palace of the Governors; a planner checks a wind rose and smiles at Philip II's old rule about streets and sun. The ordinance never stopped being good science.
Los Angeles, basement records room.
An engineer reading San Fernando traces arrows on a groundwater map. On a shelf above, a file labeled Feliz v. City of Los Angeles (1881) reminds him that some rights predate annexation and asphalt. The aquifer abides; so do the footnotes.
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X. Epilogue: two languages, one republic
America did not choose between common and civil law; it married them. When we remember that marriage—its bargains, its bilingual arguments—we judge better, plan fairer, and inherit more honestly. The country's other constitution is not hidden. It is written on plazas, in ditches, and in the codebooks of a state that refuses to forget it was born speaking two legal tongues.
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Sources (validated)
• Digest of 1808 / Louisiana civil law sources: LSU Law Center online edition; Tulane European & Civil Law Forum (Cairns) on Spanish–French sources.
• Forced heirship (current Louisiana law): La. Civ. Code art. 1493 (Justia); background on civil-law origins.
• Percheman (1833) and treaty-protected Spanish grants: Justia; Federal Judicial Center historical note.
• Laws of the Indies (1573) and town-planning rules: HUD-user translation (AGI, Sevilla); San Antonio planning history; Santa Fe planning documentation.
• Community property's Spanish lineage: Texas State Historical Association overview; comparative scholarship.
• Pueblo water rights & Irwin v. Phillips (prior appropriation): City of Los Angeles v. City of San Fernando (Cal. 1975); California case briefs and PPIC historical chapter.
• California Land Act of 1851 & diseños archive: Overview of the Act; California State Archives on Spanish/Mexican grant records.