Congress struggles on rules for cyber warfare with Iran

The U.S. and Iran may have walked back from the brink of war, but the potential for a cyber battle looms with no clear rules of engagement.

Lawmakers and military officials say there’s no agreed-upon definition of what constitutes cyber warfare, leaving them to operate on a case-by-case basis on how best to respond to individual incidents.

“We've never really gone down the route to define what constitutes an act of war when it comes to cyberattacks,” Sen. Ron Johnson (R-Wis.), chairman of the Senate Homeland Security Committee, told The Hill last week.