On June 13, 2017, Attorney General Jeff Sessions testified to the Senate Intelligence committee about Russian interference in the 2016 presidential election. After fielding hours of questions about his knowledge of the plot, Sessions was greeted by an abrupt change in topic from Senator John McCain. “Quietly, the Kremlin has been trying to map the United States telecommunications infrastructure,” McCain announced, and described a series of alarming moves, including Russian spies monitoring the fiber optic network in Kansas and Russia’s creation of “a cyber weapon that can disrupt the United States power grids and telecommunications infrastructure.”

When McCain asked if Sessions had a strategy to counter Russia’s attacks, Sessions admitted they did not.

In a normal year, McCain’s inquiries about documented, dangerous threats to U.S. infrastructure would have dominated the news. His concerns are well founded: in recent years, Ukraine’s power grid has been repeatedly hacked in what cybersecurity experts believe was part a test run for the United States. Russian hackers have also hacked many centers of U.S. power, including the State Department, the White House, and everyone with a Yahoo email address in 2014, the Department of Defense in 2015, and, of course, the Democratic National Committee, Republican National Committee, state and local voter databases, and personal email accounts of various US officials in 2016.

But while the role of hacks in the election is the subject of several ongoing probes, the hacks of other U.S. institutions and infrastructures have been largely ignored by the Trump administration, even as the hacking became more aggressive throughout 2017. In June, shortly after McCain’s testimony, the Department of Homeland Security and the FBI released an urgent joint report stating that U.S. nuclear power stations and other energy facilities had been hacked. In July, Bloomberg and the Washington Post confirmed that the hackers worked for the Russian government.

While U.S. government officials stressed that the public was not yet at serious risk, claiming the hackers had not yet gained the ability to control the grid, intelligence officers warned that infrastructure attacks by a hostile state can also operate as a form of political leverage. Most analyses of the 2016 election hacks have framed leverage in personal terms: kompromat stolen from hacked emails used to blackmail individuals into submission or to humiliate officials as part of a propaganda campaign. Less examined is the form of leverage McCain raised at the Sessions hearing: the possibility of vital infrastructure, like the power grid, being crippled, potentially causing massive financial and humanitarian consequences. In this formulation, an entire government could ostensibly be held hostage to another government’s whim out of fear of triggering a cataclysmic attack.

As 2017 wore on, Russia continued to hack infrastructure around the world , again crippling government and corporate offices across Ukraine, along with energy sectors in the United Kingdom and government officials in France, and ending the year targeting NATO countries through unprecedented focus on underwater North Atlantic cables that provide internet service to the U.S. and Europe. Disrupting these cables, one British naval official said, would “immediately and potentially catastrophically affect both our economy and other ways of living.”

In September, security firm Symantec said it had notified more than 100 energy companies in the U.S., Turkey, Switzerland, Afghanistan, and elsewhere about Dragonfly 2.0—a set of intrusions into industrial and energy-related companies suspected to originate in Russia. Using targeted phishing emails and compromised websites designed to capture users’ credentials, the hackers gained access in some cases not just to front-office networks but to “operational machines.” As a Symantec security analyst told Fast Company, “We’re talking about machines that are controlling elements that are plugged into the power grid.” A month later, the Dept. of Homeland Security and FBI warned critical infrastructure providers in nuclear, energy, and other key sectors about the ongoing attacks, noting that “threat actors are actively pursuing their ultimate objectives over a long-term campaign.”