A U.S.-Israeli-developed computer worm known as Stuxnet, generally believed to have substantially delayed Iran’s bid for nuclear weapons, evidently helped keep the world a safer place. But America and its allies obviously hold no monopoly in the developing technologies of cyber warfare.

Reiterating that point, Army Gen. Keith Alexander, head of the U.S. military’s Cyber Command, warned Monday that our nation remains highly vulnerable to potentially devastating computer attacks.

And adversarial nations aren’t the only possible source of attacks on U.S. computer systems. As Gen. Alexander pointed out during a speech at the American Enterprise Institute in Washington, “other non-nation-state actors” could do serious damage on the cyber front.

Among our vital systems at cyber risk are those at the Pentagon, Homeland Security Department and FBI. The utility and banking industries also make inviting targets for America’s enemies.

Gen. Alexander called for Congress to streamline cyber-defense initiatives before it’s too late to avert potentially devastating consequences: “The conflict is growing, the probability for crisis is mounting. While we have the time, we should think about and enact those things that we need to ensure our security in this area. Do it now, before a crisis.”

The complexities of this challenge make crafting effective strategies and policies difficult.

And there are legitimate concerns that the rush for strengthening cyber security will weaken online privacy protections.

But Gen. Alexander and other experts are right in sounding this alarm. Congress must find a way, within civil-liberties reason, to maximize America’s preventative measures against this modern menace — and to minimize response time when such attacks occur.

As Gen. Alexander put it: “We need information sharing, in time and at network speed.”

And we need to realize that in this emerging era of cyber warfare, having a good defense is at least as important as having a good offense.