The Russian hacking of Democratic National Committee servers during the recent U.S. presidential campaign was an opportunistic act. That’s the conclusion of cybersecurity expert Christopher Cleary, a former U.S. naval officer with experience at U.S. Cyber Command. Cleary believes the hack came about largely because the United States has not had a credible cyber deterrence strategy—and he’s among those calling for clearer consequences for cyberattacks.

“I personally think … that the Russians took that opportunity to poke us in the eye,” said Cleary, now the head of federal cyber programs at Tenable Network Security. “What the Russians did is saw an ability to destabilize our election, and they took a run at it.”

Cleary noted that every time the United States fails to respond to a cyberattack, adversaries become emboldened to probe our vulnerabilities until they bump up against our public “red line,” or the point at which U.S. officials will retaliate.

“I don’t think that we as a country have come up with a good enough deterrence policy to say, this is what a red line is,” Cleary told me.

Major cyberattacks in recent years include China’s hack of the U.S. Office of Personnel Management in which records of 22.1 million federal workers were stolen, an attack against the healthcare company Anthem that compromised the health records of 80 million people, and attacks by suspected Russian-government-sponsored hackers against the State Department and the White House.

The senior cyber defense official has also spoken of how the lack of a strong response to hacks only encourages further attacks.

“We’ve got to get to an idea of deterrence,” said Adm. Mike Rogers, head of U.S. Cyber Command, at a 2015 cybersecurity conference at Fordham University. “Because when I look around the world right now, my conclusion is that nation-states, groups, and individuals seem to have come in large measure to the conclusion that there is little price to pay when engaging in these behaviors.”

The U.S. Strategic Command, which oversees the Defense Department’s cyber forces, did not return a request for comment.

Michael Schmitt, chairman of the U.S. Naval War College’s international law department, told The Washington Post that hacking DNC email servers itself was not a breach of international law—but the dump of those emails to WikiLeaks reflected an intent to influence the election, an unlawful intervention into a country’s internal affairs. If Russia did violate international law by its actions, U.S. countermeasures would be lawful as long as they did not cause death or injury, Schmitt told the Post.

Such countermeasures, possibly including retaliatory cyberattacks, would likely be delivered by U.S. Cybercom’s Cyber National Mission Force, which began full operations last October. The overarching Cyber Mission Force—5,000 individuals across 133 teams—has not only a defensive mission, to protect the Defense Department and critical national networks, but an offensive mission as well.

Even if the U.S. red line remains vague, Cleary said, the creation of U.S. Cybercom and other defense measures might help send the message that the United States is serious about deterring cyberattacks.

Cancer camera

Soon, your smartphone might be able to identify common skin cancers and deadly melanomas. Using a database of about 130,000 images of skin lesions representing more than 2,000 diseases, computer scientists from Stanford University’s Artificial Intelligence Laboratory trained a Google-developed algorithm to distinguish between benign and malignant growths. During testing, the algorithm matched the performance of 21 board-certified dermatologists in correctly diagnosing benign and malignant lesions. The researchers hope to pair it with a smartphone app that would identify cancer using the phone’s camera. —M.C.