The US needs a total defence strategy

Iranian-backed hackers are suspected of attacking water municipalities across more than a dozen US states earlier this month. These are not isolated incidents. Iranian proxies have attacked or seriously threatened the American homeland multiple times since the war began in February, according to a recent report from the Department of Homeland Security. These latest Iranian-backed incidents are part of a broader trend, whereby US adversaries – including Russia and China – are increasingly attacking the country’s critical infrastructure and way of life using hybrid warfare tactics. If Washington does not quickly take steps to seriously deter and defend against these threats, it risks losing the ongoing irregular world war.

Politicians often warn about the dangers of a Third World War, which would clearly be devastating in terms of blood and treasure. But policymakers rarely acknowledge that there is another type of global conflict already happening, one fought below the level of traditional armed conflict. Because the US military remains the most sophisticated in the world in conventional terms, its enemies frequently choose to operate in the irregular warfare domain. In this ‘grey zone’ between war and peace, adversaries can deny operations and therefore often escape real consequences or escalation in risk.

In addition to Iran, more powerful US adversaries – China and Russia – are also ramping up attacks through irregular means such as cyber threats and ‘prepositioning operations’. They are also increasingly targeting US interests abroad as well as Washington’s allies, particularly those in Europe. Such attacks include recent drone and other incursions into Eastern Europe, the targeting of undersea cables in the Baltic Sea, and weaponising waves of migrants to overwhelm national borders.

Meanwhile, China has used maritime militias and island-building in the South China Sea to strengthen its position within the region. These hybrid threats are increasing in frequency, scope and cost. Last year, China averaged 2.6 million cyber-attacks on Taiwan government networks every day. Russia’s shadow war on the West has also seen a year-over-year increase in the number of acts of sabotage since 2022.

Just as America’s adversaries are intensifying their hybrid warfare capabilities and operations, the US approach to irregular warfare, and the tools at its disposal, remain largely an afterthought. The United States benefits from its geography and distance from adversaries, but the prevalence of hybrid threats specifically minimises this advantage. A few hackers could exploit vulnerabilities and shut down the country’s power grid for days on end. Significant work remains in getting the broader US government and national security community to fully embrace hybrid warfare approaches and dedicate the attention, resources and personnel needed to compete in and win the war in the shadows.

What should be done? The answer lies in making America more resilient to disruption, a form of ‘deterrence by denial’ known in Northern and Eastern Europe as total defence. Finland, Sweden and the Baltics have adapted to their proximity to Russia with a whole-of-society approach, which includes buy-in from the private sector, emphasises the role of individuals and sharpens public awareness of subversive tactics. To deter and defend against hybrid threats, Washington should take three major steps to build resilience across the federal, state and local governments – as well as across society more broadly.

First, the United States should harden its critical infrastructure and build back its now nearly non-existent civil defences. There are many ways to go about this, including ramping up cybersecurity grants and supercharging military reserve programmes. Either way, more funding is needed to shore up critical infrastructure. A $3.7 trillion investment gap in critical infrastructure spending exists in the United States. Last summer, NATO allies, including the United States, pledged to spend 1.5 per cent of GDP on critical infrastructure. The current US administration is seeking a record-high budget for the Pentagon of $1.5 trillion for 2027, with an emphasis on securing the homeland. Even if this figure is probably unobtainable, now is the time to invest in resilience at home.

Second, America should ramp up efforts to build resilience within its allies and partners, including through US Cyber Command’s ‘hunt forward’ operations, a little known but highly successful effort to build up the cyber security of key partner countries.

Finally, the United States should also draw on the expertise of the two newest NATO allies: Finland and Sweden. Finland has long championed investing in civil defence infrastructure, a unique specialisation owing to its geography and history. Sweden, meanwhile, has taken steps to reinvigorate its civil defence programmes after dismantling them following the end of the Cold War, offering a template on how to scale and prioritise civil defence from zero. A novel and as yet unexplored avenue for Washington would be to emulate Finland’s model of a national training course, which teaches civil society and industry leaders how to prepare for war.

The United States is at risk of losing the ongoing irregular world war, falling behind in the resilience race that will be key to winning it. Iran, Russia and China are leaning into this unconventional warfare at home and abroad. America’s leaders cannot afford to wait until after the next large-scale hybrid attack to take necessary action.