The New York Times today reported that the American intelligence community has determined that the regime of Kim Jong Un was “centrally involved” in the unprecedented hacking campaign against Sony Pictures Entertainment. CNN reports that the Justice Department will announce, perhaps as early as tomorrow, that hackers working for North Korea were behind the attacks, apparently intended to stop the release of The Interview, the Seth Rogen-James Franco comedy about the assassination of the regime’s supremo.

Why would the White House delay an announcement? The administration, the Times reports, “was still debating whether to publicly accuse North Korea of what amounts to a cyberterrorism campaign.” The concern is that a public accusation would result in an escalation.

North Korea, however, will escalate no matter what. If the administration tries to avoid a confrontation, Pyongyang’s leaders will of course be emboldened. They undoubtedly are pleased that they were able to get Sony today to announce the indefinite delay of the opening of the film after theater chains, intimidated by Tuesday’s threats of 9/11-type attacks, refused to show it.

Yet from Kim’s perspective, the regime has no choice but to continue the intimidation of Sony. Pyongyang, for instance, is much more concerned about the release of the film in other formats. Most North Koreans will never make it to a theater. They may, however, get to see DVDs. South Korean activists are already planning to loft them over the Demilitarized Zone in balloons.

Moreover, Pyongyang knows that it is only a matter of time before smugglers, motivated by nothing more than profit, will bring DVDs into the North across the Chinese border. For a regime that depends in large part on the image of invulnerability, the celluloid killing of its leader is itself a mortal threat.

Yet there is another reason why the U.S. must act now. North Korea is not just about North Korea. Pyongyang hackers, according to numerous reports, used Chinese IP addresses for their attacks on Sony. That should be no surprise because sources state that a North Korean cyber outfit, designated Unit 121, is based primarily in Shenyang, a city in northeast China. The unit is used to attack foreign networks, and either it or a sister organization was involved in the Sony hack. Moreover, some North Korean hackers were trained in Russia and China, according to some sources, and in 2012 Pyongyang and Tehran agreed to cooperate in cyberspace.

Moreover, for America there is a fundamental imperative to act. Washington cannot let others—whether in Pyongyang or Beijing or Moscow, or Tehran—decide what Americans read or watch.

The United States has tools to impose costs on the North Koreans. The financial sanctions put in place last decade by the Bush administration, for example, were so effective that Pyongyang, when it wanted to transfer cash, had to use its diplomats to ferry the dough in suitcases. Moreover, the crippling restrictions resulted in the North partially shutting down weapons programs for lack of funds. Unfortunately, at the behest of Beijing, Washington lifted the sanctions prematurely.

We can, due to the critical issues at stake, also go one more step and impose an embargo.

The recent attacks were directed at Sony, but they cut to the core of our free society. Washington has no choice but to respond now.

Gordon G. Chang is a Forbes.com columnist and the author of Nuclear Showdown: North Korea Takes On the World. Follow him on Twitter @GordonGChang.