NEW YORK-On Independence Day weekend, North Korea continued to flout international censure by launching 11 missiles off its east coast. Although the first four were short-range missiles and the last seven fell into the Sea of Japan, Japanese intelligence officials earlier warned the United States: North Korea, they said, planned to aim a Taepodong-2 missile, with a 4,000-mile range, at Hawaii.

Secretary of Defense Robert Gates then deployed a ground-based mobile missile system and a sophisticated radar to protect Hawaii, a move that North Korea wildly protested as a move towards "U.S. pre-emptive nuclear war."

If North Korea did launch a long-range ballistic missile, which it has not yet done successfully, U.S. space satellites that have been in space since the 1960s would detect the launch, sending basic data to a command and control center in Colorado Springs, where commanders would integrate data and engineer the defense, first exchanging data with ground-based radar in Japan, Alaska and California.

Then a Sea-Based X-Band (SBX) radar, moved to offshore Hawaii in June, would use that information to pinpoint the incoming missile and learn its characteristics, with military personnel shooting information back to the intercepting missiles in Alaska, California, and on navy ships in the Atlantic and Pacific. The SBX radar is 280 feet tall, displaces 50,000 tons, and looks like a giant golf ball balanced atop a ship larger than a football field. It can detect a baseball slammed from 3,000 miles away-or from Los Angeles to Yankee Stadium.

Once commanders receive the SBX data, they would launch the interceptors-flying several thousand miles at 15,000 miles per hour-to collide with North Korea's missile. Then they would launch the navy ship interceptors and Hawaii's THAAD interceptors. THAAD is the last defense, capable of intercepting the missile both inside and just outside the atmosphere.

Since North Korea tested a missile in April and conducted an underground nuclear test, readiness to combat a missile attack has taken on new urgency. The UN Security Council passed a scolding resolution against North Korea, stepped up sanctions and urged member states to inspect North Korea ships they suspect may be transporting banned cargo. North Korea then declared it would weaponize its plutonium and enrich its uranium. An International Crisis Group study called North Korea's motives "mostly impenetrable."

In the midst of a confrontation reminiscent of Cold War crises, the Pentagon is projecting calm resolve. Marine Corps Gen. James Cartwright, the second-highest ranking military officer, told Congress that he was "90-plus percent" confident that the system could protect us from rogue missiles. Richard Lehner, spokesperson for the Missile Defense Agency, said he agreed: "The missile could fail, but you'll still launch more than one," and three different technologies are capable of shooting a rogue missile down.

Yet as the threat from North Korea rises, the Pentagon has proposed cutting $1.2 billion from missile defense in 2010 and reducing the number of nuclear interceptors from 44 to 30. Secretary of Defense Robert Gates told Congress that 30 silos "are fully adequate to protect us against a North Korean threat for a number of years," and that if the threat evolves "then there's plenty of room . . . to expand."

This is the wrong time to lessen protection, according to Riki Ellison, chairman of the Missile Defense Advocacy Alliance, who says Gates' number is based on "budget positioning," not on intelligence reports.

Lawmakers are negotiating behind closed doors to push against the cuts. U.S. Senator Mark Begich (D-Alaska) said the Senate Armed Services Committee has marked up a bill that would reverse the Defense Department's plan to stop construction on seven of 14 proposed missile silos in Alaska. According to Ellison, other lawmakers are working on a bill calling for a study into the number of ground-based interceptors needed. As the North Korean crisis intensifies, Ellison said, cutting missile defense will be hard to justify.

(Editor's Note: This article has been edited to include a section that was accidentally omitted from the print edition.)

Pacific defense

The U.S. is sending mobile, ground-based missile-defense weapons and floating radar to Hawaii to protect the state from North Korean threats.

Sea-Based X-Band Radar

Purpose: Track enemy missile with sophisticated X-band radar

Components: Self-propelled vessel based on a modified oil drilling platform;houses living quarters, work space, radar, communications; linked to land-based interceptors

Size: 240 ft. x 390 ft.

Theater High Altitude Area Defense (THAAD)

Purpose: Intercept and destroy enemy missiles

Components: Truck-mounted launcher; missile interceptors; radar; battle management, command and control, communica-tions and intelligence units

Range: 620 miles

Naïve on nukes?

As a student at Columbia University in 1983, Barack Obama wrote praising the vision of a "nuclear free world" and rebuking "military-industrial interests . . . adding to their billion-dollar erector sets." As president, he is now negotiating with Russia to reduce the nuclear stockpile by at least one-fourth, with that same goal of reaching a world free of nuclear weapons. "I'm not naïveAlexander Aleshkin/Epsilon/Getty Images," he said in Prague in July. "This goal will not be reached quickly-perhaps not in my lifetime. It will take patience and persistence."

Tyler Wigg Stevenson, director of the Two Futures Project, a faith-based organization advocating global, multilateral disarmament, thinks Obama is on the right track: "We're not good enough to wield this kind of power." He poses this scenario: Suppose the United States weaponized RU-486, and deploying it would destroy every unborn child within miles? "Is there any evangelical in this country who would not be absolutely up in arms, who would not say this is morally unacceptable?" he asks.

Disarmament advocates like Wigg Stevenson argue that in a post-Cold War world, multilateral disarmament will take away the incentive for non-nuclear states to seek nuclear weapons. They list specific steps that they say can achieve a nuke-free world without compromising security: ratifying the Comprehensive Nuclear Test Ban Treaty (a ban on nuclear testing), negotiating a Fissile Material Cut-off Treaty (a ban on the production of fissile material for nuclear explosives), and working towards the disarmament of the United States and Russia.

Former Bush ambassador to the UN John Bolton doesn't share their faith in multilateral disarmament. "Signing on to the treaty gives a false sense of security," he told me, noting North Korea and Iran have blatantly ignored the Nonproliferation Treaty (NPT). When it comes to verifying and enforcing the treaties, he said, "Every technological step forward gives you a little bit greater confidence, but when you're talking about questions of potential mortal threat to the United States, you need a little bit more than that."

Bolton wrote in USA Today on July 9, "Obama's policy is risky for America and its global allies who shelter under our nuclear umbrella. Although Obama hopes dramatic U.S. nuclear weapons reductions will discourage proliferation, he said, "the actual result will be the exact opposite."