Brazil's Marco Civil law contains vigorous language intended to protect free expression, and a stable, secure and neutral network in Brazil. But as we have noted before, such laws must be interpreted and enforced appropriately to be effective. A good Internet law can quickly turn bad if incorrectly or improperly applied.

Last week, a Brazilian municipal judge sought to wield one part of the Marco Civil—its section on mandatory data retention—in a way we think undermines the rest of the law. Judge Luiz de Moura Correia of the Brazilian state of Piauí ordered Brazilian Internet and mobile connectivity providers to block access to the WhatsApp mobile-messaging application within 24 hours. The judge told journalists the injunction was intended to “compel the company that owns the app to assist with investigations by the state police.”

Correia's decision would have affected millions of innocent Brazilians who rely on WhatsApp as a messaging service. It would have served as a disturbing indication that in the pursuit of one aim of the Marco Civil, the courts can trample over the freedom of users to communicate online, and the freedom of the Net and the tools used to access it to remain uncensored.

Brazilian local courts have had a long history of issuing such broad and disruptive injunctions in their attempts to force Internet intermediaries to comply with state investigations or orders. Two examples have become especially well-known. In 2007, after YouTube failed to take down a clip of Brazilian supermodel Daniela Cicarelli, a São Paulo state court issued an order that led to the entire YouTube service being blocked by Brasil Telecom. In 2012, a Judge in Mato Grosso do Sul ordered a 24-hour suspension of Google and an arrest order for the head of Google Brasil after the company failed to remove videos critical of a mayoral candidate.

It was in this earlier atmosphere of random and disruptive court orders that the Marco Civil was born: an attempt to create a general and consistent set of principles under which the Brazilian Internet would be governed. The Marco Civil goes to great lengths to establish that Brazilian law should treat the Internet as a force for free expression, with the stability of the network and the protection of privacy as key "disciplines" of the new law.

Unfortunately, Judge Correia used the most freedom-unfriendly parts of the new law as the justification for his order. The Marco Civil includes a series of punishments that can be ordered against companies that do not comply with various regulations, including warnings, fines, service suspension and outright prohibition. Judge Correia's order selected the most severe of these sanctions, and interpreted it as authorizing censorship orders to ISPs.

The injunction against WhatsApp was halted on Thursday by an appeals court, the Piauí Court of Justice, which determined that the injunction was unreasonable because of the disproportionate effect of a suspension of service would have thousands of Brazilians unconnected with the local investigation.

As Paulo Rená, director of IBIDEM, activist and former manager of the Marco Civil consultation process, told EFF:

The measure itself lacks explicit or implicit support within the principles granted by the law, which ensures the social purpose of the Internet, the citizenship in digital media, the preservation of stability, security and network functionality, and the collective interest.

Legal experts Ronaldo Lemos and Celina Beatriz, both of the Insituto de Tecnologia e Sociedad do Rio (ITS Rio), also questioned the propriety of ordering ISPs to shut down access to a service, telling Brazilian press that the blocking of the service was not a remedy authorized by the law.

Moreover, Brazil has ratified the International Covenant on Civil and Political Rights as well as the Inter-American convention on human rights, which both protect free expression, and it can only be limited in very narrow cases and when necessary and proportionate.

Judges and lawmakers around the world continue to reach for censorship and mandatory blocking to enforce local law on a global Internet. It's a clumsy, disproportionate response that sacrifices the rights of millions and the promise of an uncensored Internet to exact the narrowest of concessions. Overturning the order sends the right signal about the Internet's future; but the fact that such injunctions can still be made in the first place, and users faced with censorship of foreign apps and services, even in the home of the Marco Civil, shows how far we have to go.