Among the questions raised by President-elect Barack Obama's victory, one has been largely overlooked by his critics and supporters: What fate awaits the international missile defense system Washington has been building over the past decade? After all, as is his way, the president-elect has been both for and against missile defense.

Before trying to decipher Obama's position on missile defense, it pays to recall the remarkable progress missile defense has made to date.

Critics of missile defense--and of President George W. Bush--believe it was Bush who forced the issue and pushed missile defense from the realm of theory into the arena of international politics. In fact, this shift began in the late 1990s, after a congressional commission raised a number of warnings about ballistic missile threats and, as if on cue, North Korea test-fired a three-stage rocket. President Bill Clinton then signed legislation that paved the way for deployment of a system to defend against "limited ballistic missile attack as soon as is technologically feasible."

Clinton's critics say he could have done more, which is true. But he also could have done much less. In the end, he followed the Hippocratic Oath when it came to missile defense: He did no harm.

By endorsing missile defense, Clinton reflected the emergence of a national consensus on the issue. As Gen. Henry Obering, director of the U.S. Missile Defense Agency (MDA), observes, today's missile defense program is the product of four administrations, 11 Congresses and $115 billion in U.S. investment.

Thanks in part to that consensus, Bush was able to accelerate the program.

First, he notified Moscow of America's intentions to scrap the anachronistic ABM Treaty. He promised to slash America's nuclear arsenal from 6,000 warheads to 1,700 and assured the Russians that missile defense wouldn't upset the U.S.-Russia balance of mutual deterrence. At the time, Vladimir Putin agreed, concluding that Washington's decision "does not pose a threat to the national security of the Russian Federation." (Russia's recent reversal is a subject for another essay.)

By early 2003, Bush was building a missile defense coalition. The British government agreed to upgrades of radar stations in the UK. Denmark approved similar upgrades at radar and satellite-tracking stations in Thule, Greenland.

In late 2003, Tokyo gave the go-ahead for construction of missile defenses, in close partnership with the United States. Australia and the United States signed a 25-year pact on missile defense in 2004. That same year, the United States began deploying interceptor missiles in Alaska and California, adding a new layer to the missile defense system.

No less than 18 nations are now partnering with America on missile defense--a function of the growing global threat posed by ballistic missiles. ?Three decades ago, there were nine countries that possessed ballistic missiles. Today, there are 32. By my count, 12 of them are unfriendly, unstable or uncertain about their relationship with the West. With their twin terror programs that seek to match rockets with nukes, North Korea and Iran top this list.

In July, according to Obering, "Iran orchestrated launches of several short- and medium-range ballistic missiles capable of striking Israel and the U.S. bases in the Middle East." Just days after Obama's election, Iran tested a two-stage, 1,200-mile-range, solid-fuel rocket. At that range, the missile would be able to hit targets in southern Europe. The Defense Intelligence Agency "estimates that Iran could have an ICBM capable of reaching the United States by 2015," Obering notes, ominously adding, "We should not assume that we have full understanding of ballistic missile activities around the world. We have been surprised in the past."

That brings us to the paranoid regime in North Korea. Over the past decade, Pyongyang has tested long-range rockets and detonated a nuclear weapon--both coming as stunning surprises to Western intelligence agencies. In September, we learned that North Korea conducted tests on engines for a new long-range missile and constructed a new facility for ICBM tests--and launches.

"It would suggest," warns John Pike of GlobalSecurity.org, "they have the intention to develop the capability to perfect a missile to deliver atomic bombs to the United States."

Yet if proliferation gives us reason to worry, missile defense's important strides this year offer reason for hope.

• On the diplomatic front, NATO officially endorsed the missile defense system during its Bucharest summit.
• In August, Poland and the United States agreed on deployment of missile defense interceptors on Polish soil. (Of course, Moscow announced this month its intention to deploy missiles and jamming equipment in neighboring Kaliningrad.)
• Beyond Europe, Washington and the UAE announced plans to cooperate on deployment of the Terminal High Altitude Area Defense system. Sitting just across the Persian Gulf from Ahmadinejad's Iran, the UAE would be a prime target for Iranian missiles in a time of hostilities. According to the State Department, the UAE "hosts more U.S. Navy ships than any port outside the U.S."
• On the capabilities front, the Airborne Laser (ABL) was successfully tested in September. Mounted on a 747, the ABL will be able loiter just outside enemy territory and intercept missile threats long before they enter allied airspace.
• Those threats that the ABL can't thwart will be engaged by a growing number of sea- and ground-based assets. There are already 15 Aegis warships equipped with SM-3 interceptor missiles, with three more set to be deployed by the end of 2008. We glimpsed the real-world capabilities of these ships in February 2008, when the USS Lake Erie intercepted a falling satellite--traveling 17,000 mph 150 miles above the earth--with an SM-3.
• In addition to naval assets, there will be 30 ground-based interceptors at U.S. sites by the end of the year. By 2011, according to Obering, the U.S. will have 44 interceptors at U.S. sites, with 10 more on the way in Europe by 2012--that is, unless the new commander-in-chief issues new orders.

That brings us back to the Obama administration. Candidate Obama was emphatic about his opposition to missile defense--sort of.

For example, during the campaign, Obama vowed, "I will cut investments in unproven missile defense systems."

But he said something much different during a debate with Sen. John McCain. "I actually believe that we need missile defense, because of Iran and North Korea and the potential for them to obtain or to launch nuclear weapons," Obama intoned.

He found a line somewhere in between those positions after a post-election phone call with Polish president Lech Kaczynski, who felt reassured by Obama's promise that "the missile defense project would continue," in Kaczynski's words. But an Obama adviser painted a dramatically different picture of the exchange, reporting that "President Kaczynski raised missile defense, but President-elect Obama made no commitment on it." The incoming president, he added, "supports deploying a missile defense system when the technology is proved to be workable."

That's a typical trope of missile defense opponents, and it likely reveals Obama's real views on missile defense. Opponents of missile defense use words like "workable" and "proven" to set such a high standard for missile defense that anything less than a 100-percent intercept rate means the system is "unproven" or "unworkable."

To be sure, the missile defense system has failed tests from time to time. Just this month, for example, the Navy reported that a pair of Aegis destroyers intercepted one missile and missed another during tests off Hawaii. But since 2001, as Obering has noted, missile defense assets have scored successes on 35 of 43 hit-to-kill intercepts, or 81.39 percent of the time. A growing global coalition prefers those odds over the zero-percent chance of success guaranteed by shutting down the missile defense program or consigning it to the lab.

This is one campaign promise we should hope President Obama breaks.