The Obama administration is reacting to the anticipated launch of another North Korean long-range ballistic missile, expected to fly over the Pacific toward Hawaii sometime soon, by putting missile defense on alert.

That's a big change from last time.

Back in April, in advance of North Korea's last missile test, the administration pretty much pooh-poohed the threat posed by the Taepo Dong launch, characterizing Pyongyang's saber-rattling as bluster.

Indeed, from all outward indications, Team Obama did just about nothing but bloviate to defend US territory and interests from the missile that, by almost all accounts, has the potential to reach the western United States.

The Pentagon even declined to put the Pacific missile-defense system (based at Fort Greely, Alaska, and Vandenberg Air Force Base, Calif.) on operational alert -- precautions the Bush administration took during North Korea's 2006 Taepo Dong test.

But the April shot saw the Taepo Dong fly further than ever before -- some 2,500 miles. That relative success apparently surprised and embarrassed the White House enough that it's taking a drastically different approach this time by deploying just about all of the bells and whistles in our (still limited) missile-defense arsenal.

It's a layered Defense: An at-sea X-band radar will cue shooters with sensor data to engage the incoming missile. Ground-based missiles from Greely and Vandenberg will intercept the missile in mid-flight. And if those countermissiles don't score, Navy Aegis-class destroyers at sea off Hawaii and land-based THAAD (Terminal High Altitude Area Defense) systems on Hawaii will destroy the target.

It's the right thing to do, but what changed? Pretty clearly, the Obama crew got mugged by reality.

Their charm offensive toward North Korea isn't working. Pyongyang has been as belligerent as ever, lobbing more threats, epithets and missiles in our direction than at any time in recent history.

In fact, the Kim Jong Il regime is ratcheting up tensions in an almost unprecedented manner -- while it's clearly getting closer to having a nuclear-capable missile that can "reach out and touch us" in a very bad way.

Moreover, insiders say that field commanders seem to have convinced Defense Secretary Bob Gates that they weren't comfortable with doing nothing to defend their areas of responsibility this time around. In fact, the Obamanistas may just have come to realize that, despite their deep-seated dislike for missile defense, it's the best tool they've got for protecting American troops, territory and interests against these North Korean missiles.

Indeed, whether or not the administration will acknowledge it, missile defense has proven an effective system based on dozens of successful tests. Sure, the technology is still evolving, but it's already shown it can "hit a bullet with a bullet" in space: Now we're even able to hit a particular spot on that "bullet."

Deploying missile defense in the face of continuing Korean hectoring also helps the administration counter the perceptions (domestic and international) that it's weak on national security. Indeed, this allows the Pentagon to act militarily, but in a way that's relatively unlikely to provoke escalation by the other side.

It's certainly more subtle than stationing a carrier strike group off the Korean coast.

The good news is the Bush administration kept its promise to develop and deploy missile defense to protect us against an expanding nuke and missile threat. Otherwise, we'd now be completely vulnerable to North Korean missiles.

The bad news is the new team hit the brakes on developing the Pacific missile-defense system further, halted the development of a European system to protect us against the unfolding Iranian threat and cut the missile-defense budget by 15 percent.

Maybe North Korean menacing will finally convince the administration and Congress that being able to protect yourself with missile defense is really a good thing. It certainly beats the alternative -- "Duck and Cover."

Peter Brookes is senior fellow for National Security Affairs in the Davis Institute at The Heritage Foundation.