This time it's a movie you won't be able to see. Next time it could be cash you can't withdraw, flights you can't take, lights you can't turn on or water you can't drink.

That's the looming danger in the recent cyber-attack and threat of terrorism that caused theaters to refuse to screen the film "The Interview," and then forced Sony Pictures Entertainment, a subsidiary of a Japanese company, to cancel its Christmas release.

President Barack Obama initially linked North Korea to the attack that its leader, Kim Jong Un, may have ordered in a fit of pique over a film comedy about a CIA plot to assassinate him. If it turns out that North Korea is the culprit, then this episode is an unsettling glimpse of a future of state-sponsored cyberterrorism that comes perilously close to an act of war.

No nation can be allowed to block commerce in this country, sabotage a company doing business here, threaten American lives and get away with it. Unlike the exploits of merely mischievous hackers, this provocation is a serious, precedent-setting threat to national security.

The administration must make sure it has convincing evidence of who is to blame. Some experts have questioned whether North Korea has the sophistication to carry out such a hack attack. But over the summer North Korea warned that the film's release would be an "act of war that we will never tolerate," and said the United States would face "merciless" retaliation. It could have tapped tech-savvy mercenaries to do the deed.

If North Korea proves to be responsible for the attack, then Obama must make sure the rogue nation pays. A proportional response is the best way to deter future attacks. But while easy to say, that's probably not so easy to do.

North Korea is already under stringent economic sanctions imposed by the United Nations in an effort to curtail its nuclear weapons program. More of the same economic pressure would be an inadequate response to this latest outrage.

The United States hasn't been physically attacked and, fortunately, officials have uncovered no specific plans to act on the hackers' threat of mayhem at theaters or worse. So traditional military responses should be off the table.

Retribution should come in cyberspace, where the attack was launched. Its unclear what cyberwar capabilities our nation has to deploy against whoever is responsible. But there has to be some appropriate weapon in our arsenal.

The resolve that the United States must now show the world about not tolerating cyber-attacks linked to terrorist threats should be buttressed by private companies that should refuse to kowtow to intimidation.

Sony said it has no plans at the moment to make the "The Interview" available to consumers either in theaters or online. But at some point, very soon, Americans ought be allowed to see the movie North Korea is apparently so desperate to censor.