WASHINGTON—Telma Ortiz, the sister of Spain’s future queen, caused a commotion recently by seeking a restraining order that would have barred more than 50 media outlets from taking pictures of her except in public functions. She asked the court to protect her right to privacy, claiming that she is not a public person—just the sister of Princess Letizia, a commoner who married the heir to the throne in 2004. The case has gained international attention not least because celebrities who are constantly at war with paparazzi were hoping for a precedent. But the Spanish court ruled against Ortiz. Who is right?

Ortiz says she has been “harassed” by the media ever since she and her boyfriend came back from the Philippines, where she was an aid worker, in order to give birth. She has accused the paparazzi of imperiling her life.

Some commentators have argued that this case differs from other lawsuits frequently brought by celebrities against media organizations because Ortiz was not arguing against the invasion of a public figure’s privacy, merely against the media treating her as a public figure. The judge decided that she is a public figure whether she likes it or not.

Yet the real issue is not whether Ortiz is or is not a public figure. Rather, it is whether the media can rightfully take pictures of her when she walks out of her home and steps into a space that is “public” in order to perform what she considers a “private” function, such as going to a pharmacy or pushing her baby’s stroller on the way to the park.

I wonder what the Founding Fathers of the United States, pretty good counselors when it comes to matters of individual rights, would think. Interestingly, the word “privacy” does not appear anywhere in the Constitution or in the Bill of Rights—only the word “private,” in reference to property. What can we infer from this? The concept was either too vague to be the object of a specific limit on government, or it was implicit in the individual rights spelled out in the Constitution: life, liberty and private property. To the extent that the word “private” is attached to property and never mentioned on its own, we can probably conclude that the Founders thought property was the essential fact in a person’s privacy—whether property of one’s body, one’s actions or one’s possessions.

That would mean, translated into 21st-century Spain, that the media cannot cause Ortiz physical harm, trespass on her property in order to film her, cause her to lose money by having to slow down on her way to a meeting and thus miss it, or prevent her from walking into a store. But, barring those types of invasions, the media are free to use the public space and therefore film her on the streets.

Ortiz is right about one thing: A good part of the Spanish press can be insufferable when it comes to celebrities—just like in most other free countries. And she has certain rights that no one, including the media, can ignore. There may well have been occasions when these rights were violated and Ortiz could have sued the paparazzi with a very good chance of winning. It would also be advisable for the media to exercise much better judgment of what is and what is not newsworthy when it comes to the sibling of a princess, and to simply show more respect for someone who is clearly in some distress (a sister of hers committed suicide not too long ago). But if the courts, or legislators for that matter, were to prevent the media from taking pictures of her in places that are not owned by her, they would be granting her the same right that she has when she is inside her own house—i.e., the “private” property of the parks, sidewalks or beaches she happens to frequent.

The public nature of spaces beyond one’s property is the real issue here. A space that is owned by everyone and therefore by no one in particular is bound to give rise to competing claims. But unless the Spanish government were to privatize every public place in that country, there is nothing the authorities can really do to accommodate Ortiz’s wishes without violating someone else’s rights.