Federal lawmakers are considering suspending a critical element of America's missile defense system, saying they want to shut down an unproven new technology and shore up public savings.

But gutting the Ground-based Midcourse Defense system would seriously undermine national security. Missile defense has never played a more important role in protecting Americans and keeping global threats in check. 

The "Exoatmospheric Kill Vehicle," or "EKV" for short, is the fancy name for the part of a missile defense rocket that actually collides with incoming ordnance. Using sophisticated radars, a defense system first detects an enemy missile. It then launches a multi-stage rocket that, once it exits the earth's atmosphere, ejects the EKV. The EKV then navigates its way to the targeted missile, and hits and destroys it. 

Right now, the United States has 30 EKV units in operation. 14 more are under development and are planned to become operational by 2017. Because so much of the technological legwork has already been done, investing in new EKV units is an efficient use of taxpayer resources; engineers don't have to build a brand new system from scratch. And keeping this system perpetually progressing guarantees our country will always be protected by the most advanced missile defense technology available. 

However, some of the new EKV prototypes are failing in testing. They're missing their targets.

Such failures aren't unusual in the weapons development process. After all, these are incredibly sophisticated systems attempting to hit a target going thousands of miles per hour in suborbital space. Also, the basic design of the EKV itself has not changed since the original test prototype was rushed into service. The components are based on 10 year old-plus technology, and unnecessarily complex when compared to today's state of the art. 

Given a normal development program, defense developers have already proven they can turn around once-flailing projects in a timely manner. Consider the Standard Missile-3 (SM-3), a sea-based interceptor that targets short- to intermediate-range missiles. It also suffered some failures in early testing, but after an additional infusion of resources the kinks were quickly worked out. SM-3 has now successfully intercepted missiles in space 26 times. The lesson learned is to upgrade an existing and capable system, rather than starting over.

Appreciating these nuances, the top military brass has proposed investing another $560 million into EKV development to fix the problems uncovered by these tests. That's about one percent of what's apportioned for missile defense of the next three years. In terms of the overall federal budget, it's a drop in the bucket.

However, some in Congress are pushing back. They don't want the EKV salvaged -- they want it shelved, in favor of starting over with a brand new replacement technology.

That might make things even worse. Starting over from scratch would waste an enormous amount of time and money. And scrapping it would leave our existing missile defense architecture bereft of an essential component for several extra years. 

That's dangerous. Effective missile defense isn't a luxury in the modern global security environment -- it's a necessity. Consider the key threats to America.

North Korea's nuclear missile program proceeds apace, with the stated goal of being able to launch a pre-emptive attack on the United States. Iran's nuclear weapons program is speeding forward as well. That country's ruling elite continues to spout apocalyptic visions. 

These people can't be bargained with. 

That's why missile defense is so crucial. We have to be ready in case they strike first. And we need our technologies to evolve to meet the increasingly sophisticated missiles being developed by rogue regimes. As Admiral James A. Winnefeld, Vice Chairman of the Joint Chiefs of Staff, recently stated in his keynote address at this year's Missile Defense Conference, "a robust and capable missile defense is our best bet to defend the United States from such an attack."

That's why we can't afford to wait to build an entirely new replacement for the EKV. Investing and fixing today's capable system with existing technologies takes a lot less time and will ensure our defense systems will be fully operational as quickly as possible.

Scrapping the EKV would needlessly delay our ability to improve our missile defense shield, and would leave us more vulnerable to dangerous rogue regimes.

Grant, Ph.D., is president of IRIS Independent Research, a Washington-based public-policy research organization.