Since taking office, President Joe Biden has ordered a thorough intelligence review of Russian aggression around the world, which includes hacking, election interference, poisoning political opponents and posting bounties for killing U.S. soldiers. His administration faces pressure from members of Congress in both parties and former government officials to respond forcefully to the SolarWinds breach. But the U.S. government may not be able to stop future intrusions into American computer systems. Scholarship describes how difficult it can be to effectively deter cyberattacks or punish those responsible, and suggests that retaliation – in whatever form it might take – will almost certainly invite counterhacks from Russia, worsening tensions between the countries and potentially escalating into the offline world.