Righthaven has become controversial by taking a sue-first-ask-questions-later approach to copyright enforcement on behalf of its newspaper clients, which include MediaNews Group as well as the smaller chain that owns the Las Vegas Review-Journal. Most content companies, by contrast, are content with more low-key methods of making sure their copyright is respected. But if the Righthaven experiment ends badly, it could be a big setback for other media companies trying to make sure their content isn’t copied—even for companies that wouldn’t ever consider an aggressive strategy like Righthaven’s. There are at least two ways that could happen.

Consider the most common form of copyright enforcement on the web. It isn’t a lawsuit filed in a federal court. It’s often a simple note asking a website to simply take down the copied content. That might come from a lawyer, or an editorial employee, and the tone can range from threatening to friendly. Even without the expense of a lawsuit, content owners know that they can at least send a request to stop another site from posting a full copy of a text article or other work and know they’ll be taken seriously. Even a polite e-mail asking a site to limit itself to a partial quote with a link back is a request that relies, indirectly, on the power of copyright to stop digital copying.

For all the gray areas around what’s legal and illegal when it comes to repurposing content in the digital era, there’s one basic copyright principle people agree on in nearly every situation—and you don’t need to be a lawyer to figure out: You can’t make a whole, perfect, 100% copy without permission.

But depending on how the Righthaven litigation pans out, these types of cases could become much less clear cut—because we might be about to see 100% copying become legally justified in many situations.

Two ways that could happen:

A judge could rule that newspapers gave “implied license” to copy their content. That means that the newspaper already gave readers permission to freely copy its work, at least for non-commercial purposes. The logic goes like this: both of Righthaven’s two biggest newspaper clients, The Denver Post and the Las Vegas Review-Journal, have a set of tools next to their online stories that directly encourage readers to “share” that content. (For example, check out this widely litigated article about the Vdara Hotel, and its accompanying “tools” section encouraging readers to share the story on Facebook and other social networks, as well as make personal copies by saving or printing the article.)

Lawyers for some Righthaven defendants are arguing that the Review-Journal can’t, on the one hand, encourage readers to share—which always involves some copying when done with a computer—and then file a lawsuit demanding to be paid for the copying that they encouraged. Defense lawyers for Jan Klerks, who runs the non-profit website skyscrapercity.com and was sued in May, put it like this: “[The newspaper] encouraged people to save links to the work or to send links to the work to others anywhere in the world at no cost and without restriction. The Las Vegas Review-Journal website also enables third parties to ‘right click’ and copy the text of articles on the site. Accordingly, based on this implied license, the allegedly infringing copy was, in fact, authorized by the Las Vegas Review-Journal and therefore, is not an infringement.”

The implied license argument is already being made in at least one other case in addition to Klerks’ case.

Or, a judge could rule that even full copies of newspaper articles are often “fair use.” Fair use is the most important limit on copyright; it enables everything from the quotes a critic uses in a book review to a system like Google’s Image Search. Determining fair use isn’t always simple; in court, a four-factor test is used that considers the proportion of the work used, the purpose of the use, and other factors. But there are hardly any examples where copying 100 percent of a text article of any length has been found to be a fair use; so content owners can usually feel confident in asking a website engaged in full-scale copying to remove the content.

But now some attorneys who are Righthaven critics are saying that defendants do indeed have the right to copy entire newspaper articles without permission, arguing that it’s fair use. One example: UC Berkeley Law Professor Jason Schultz wrote a brief [PDF] condemning Righthaven’s position that use of an entire work can’t possibly be fair use. Schultz’s brief, on behalf of an Oregon non-profit called the Center for Intercultural Organizing (CIO), argued that the group’s re-posting of a Review-Journal article should be fair use because it served a completely different audience than the R-J—immigrants residing in Oregon—and didn’t hurt the R-J‘s market for its work at all.

In a preliminary hearing in the CIO case, a Las Vegas federal judge seemed skeptical that the non-profit’s re-posting of a newspaper article had hurt the R-J at all. “You really think the defendants are competing with the Review-Journal and making a ton of dough on this?” asked U.S. District Judge James Mahan asked. according to a Las Vegas Sun reporter who attended the hearing.

If Mahan or another Nevada federal judge makes a strong ruling in favor of a full-copy fair use, it could change the business practices of media-company lawyers, who are used to freely asking for takedowns of full online copies. Mahan has already ordered Righthaven to explain why he shouldn’t dismiss the lawsuit against CIO; a hearing is scheduled for Feb. 22.

In fact, companies experimenting with other types of copyright enforcement are relying on the fact that 100% copies aren’t authorized. For example, during a recent study of how rogue websites reacted to copyright requests, anti-piracy company Attributor created an automated system looking for copies of text articles that were at least 80 percent copied from an original text of at least 125 words. The point was to limit the test to sites that were indisputably engaged in copyright infringement—the clear-cut cases.

But that basic assumption may no longer hold true moving forward.