With Ted Cruz the victor of the first contest of the GOP nominating calendar, we can no longer avoid the question mischievously posed by Donald Trump: Is Cruz ineligible to be president? Cruz was born in Canada to an American mother and a Cuban father. The Constitution says that only a “natural born citizen” can be president. Is Cruz a natural born citizen? (You may recall that before he attacked Cruz on this front, Trump spent months flogging a ludicrous version of this critique against President Obama, who was actually born in the United States, unlike Cruz.)

The words natural born citizen, and their original meaning at the time that this constitutional clause was crafted, go a long way to answering this question. In founding-era America, like today, a person could be a citizen by virtue of birth on American territory; a citizen by virtue of a statute that granted citizenship to him at birth; a “naturalized” citizen, meaning one who entered the country as an alien but later obtained citizenship via a process determined by law; and a foreigner.

A natural born citizen cannot be a foreigner. Foreigners are not citizens. A natural born citizen cannot be a person who was naturalized. Those people are not born citizens; they’re born aliens. Most important for the purposes of the Cruz question, a natural born citizen cannot be someone whose birth entitled him to citizenship because of a statute—in this case a statute that confers citizenship on a person born abroad to an American parent. In the 18th century, as now, the word natural meant “in the regular course of things.” Then, as now, almost all Americans obtained citizenship by birth in this country, not by birth to Americans abroad. The natural way to obtain citizenship, then, was (and is) by being born in this country. Because Cruz was not “natural born”—not born in the United States—he is ineligible for the presidency, under the most plausible interpretation of the Constitution.

The historical background supports this view. In the founding era, it was possible—even common—for a head of state to be foreign born, and even to be a foreigner. The then-king of England—George III—descended from the German House of Hanover. His immediate predecessors—Georges I and II—were German born. William III—who came to power in the Glorious Revolution of 1688, which initiated the constitutional monarchy headed by the Georges—was himself Dutch. In the 1600s, the crown was passed among another group of foreigners—the House of Stuart. James I, who was jointly king of England and Scotland, was Scottish born, as was his son, Charles I.

The English tolerated foreign rulers because the rules of dynastic succession were widely accepted at the time. But the English resented and distrusted their foreign monarchs. After deposing James II—who as a Catholic, and a cousin and ally of Louis XIV of France, was suspected of foreign sympathies—Parliament banned Catholics from the throne. Moreover, Parliament declared that the nation would not be obligated to fight in defense of foreign dominions of a British king who is not “a native of this Kingdom of England.”

The founders admired the British form of government and modeled the president after the king. The risk that a person with foreign connections and sympathies might seize the presidency would have been uppermost in their minds when crafting the language that determined who could hold office. Other provisions in the Constitution ensured that members of Congress had significant attachments to the United States, though they could be foreign born; in the case of the presidency, the founders used stronger language.

Cruz’s defenders point out that many of the founders were lawyers who were familiar with British law, which prevailed in the colonies before the Revolution. While in the common law “natural born subjects” of the British crown meant people born on territory controlled by the British king, Parliament passed several statutes in the 17th and 18th centuries that gave the foreign born children of British subjects the status of “natural born subjects.” The founders, when they used the term “natural born Citizen,” may well have had this broader interpretation in mind, as argued by law professor Michael Ramsey in a comprehensive and carefully reasoned academic paper.

However, the statutes typically provided that a foreign born person would be considered a natural born subject for all “intents and purposes.” As legislatures often do, Parliament preferred using a comprehensive legal fiction (a person born abroad is treated as if he were natural born even though he is technically not) to using cumbersome new language piecemeal (explaining, every time new laws are passed, that they applied to foreign born subjects as well as natural born subjects). Parliament did not change the ordinary meaning of the words natural born; it just gave other people the status of those natural born.

Legislators create laws, not words: The ordinary meaning of natural born stayed the same even while legal fictions created by statutes proliferated. Similarly, the ordinary meaning of the word person is human being even though Congress has provided that corporations are persons for certain purposes. When most citizens at the founding read natural born, they must have assumed someone actually born in the country, just as today when you see the word person in the newspaper, you don’t assume that that the reporter means a corporation as well. To naturalize an alien is to confer citizenship status but not to somehow convert him to having been born in America; similarly, to confer citizenship by statute to someone born abroad to an American parent is not the same thing as retroactively making that person born in this country—making him natural born—which would be impossible.

Times have changed since the 18th century. I doubt that a President Cruz would try to bring America under Canadian control. And I’m not worried that Americans will hand the presidency to Vladimir Putin or David Cameron. But Cruz, whose campaign website has a section headed “RESTORE THE CONSTITUTION,” believes that the Supreme Court has gone astray by refusing to enforce the original understanding of the Constitution. If he’s right, then he’s not eligible for the presidency.