As we turn the page to a New Year, members of Congress and their staffs will face a myriad of difficult questions regarding how best to protect our homeland from a growing number of threats to our national security. In this era of declining budgets, it is critical our top national priorities are sufficiently resourced to provide those at the "tip of the spear" with the tools to protect our homeland from existing and emerging threats.

One such threat emanates from the growing number of ballistic missiles being developed by rogue adversaries. Given that this threat is growing in both quantity and sophistication, funding for our nation's ballistic missile defenses must remain at the top of America's priority list.

Deliberations will soon begin on how best to invest in the missile defense programs and technologies vital to keeping us safe. At the top of the list of budget priorities is the Ground-based Midcourse Defense (GMD) system, which provides the United States the capability to engage and destroy limited intermediate- and long-range ballistic missile threats in space.

The GMD is a robust system in which our war fighters have absolute confidence, even if the system has faced technical challenges and requires continual improvements and upgrades. After all, what successful system doesn't?

Surprisingly, some continue to question the efficacy of its "hit-to-kill" technology used to defeat an incoming re-entry vehicle. These hit-to-kill "non-believers" choose to ignore clear evidence that the technology works. Single-shot GMD flight tests (the military could use more than one in any actual engagement) were completely successful in five out of the last eight tests, including the most recent flight test on Jan.uary 28.  , 2016.

Similar "hit-to-kill" technologies used in shorter-range systems have been successful in a combined 53 out of their last 61 flight tests. It is the most effective tool the war fighter has to defeat an incoming re-entry vehicle from a ballistic missile threat.

Given that the system is proven to work, and that the threat continues to grow, we must continue to maintain our commitment to this vital element of our nation's defense. Congress must hold firm on funding allocated to build our inventory of ground-based interceptor missiles from 30 to 44 by the end of calendar year 2017 to pace the threat.

Some in Congress have suggested that constructing a third GMD site, sometimes referred to as the "East Coast missile site," should be a priority. In a perfect world of unlimited resources, this might be true; but the reality is that a decision to construct the new site would come with significant material development, sustainment and opportunity cost detrimental to our other near-term priorities.

It is imperative that we proceed sensibly — we simply cannot afford to invest precious resources in a third site at this time, while so many other critical needs exist first.

Particularly critical is funding to redesign the GMD's exo-atmospheric kill vehicle (EKV). This redesigned kill vehicle, or RKV, will be built with a modular open-architecture design with common interfaces and standards, making future upgrades and improvements more efficient and cost effective. The RKV is not a complete redesign, but builds on and enhances a proven system and does so with cost in mind.

Some have suggested that the RKV be scrapped in favor of a more advanced Multi-Object Kill Vehicle (MOKV). While the MOKV is an important part of homeland missile defense's longer-term future, it is critical we remain committed to RKV.

The redesign will result in a kill vehicle that is much more reliable, producible and testable than the existing model, and be delivered much sooner than the MOKV could be developed. The methodical systems engineering rigor required to develop the RKV will provide invaluable lessons for much of what the MOKV becomes — for example, the ability to communicate from one kill vehicle to another — but to leap-frog this critical developmental step would potentially be a multibillion dollar mistake we cannot afford to make.

There are several other key priorities critical to ensuring that the GMD stays ahead of the advancing threat. Foremost among them is funding to enhance discrimination for enhancements to near and midterm targets, and discrimination to improve missile engagement reliability and lethality. The long-range discriminating radar, awarded in 2015 and slated for operation in Alaska in 2020, will enhance the complex array of networked sensors and provide better tracking and discrimination of threats.  

The end result of these programs will be a system more capable of neutralizing an adversary's re-entry vehicle with a high degree of confidence and that will dramatically improve system capability and war-fighter efficiency, ultimately preserving vital interceptor inventory. Continued funding for the versatile Sea-Based X-Band Radar platform will also contribute greatly to this end.

While much of the debate on Capitol Hill focuses on the virtues of an East Coast GMD site, Congress must recognize that with limited defense dollars there are more urgent priorities. for the warfighter. These include upgrades to the existing network of sensors, command-and-control nodes, funding for a robust flight-test program, and the infrastructure and ground systems, all necessary to ensure our success.  

Also important is funding for scientific research and development for missile defenses of the future, such as efforts in space or near-space-based discrimination, an electromagnetic railgun, directed energy, and other methods of non-kinetic kill.

As decision makers prepare to make the difficult choices to deter aggression, protect our interests, and pursue cost- and operationally effective missile defense capabilities, against current and future threats, they must protect those programs vital to the safety and security of the United States and its citizens. 

The best option is to stay the course, and continue to refresh and upgrade the GMD system while balancing it with other elements of deterrence. Without the critical funding necessary for these continued missile defense advancements today, our tomorrow stands at risk.

Retired USAF Brig. Gen. Kenneth Todorov is president of Go4ward LLC, a Washington area national security and leadership consulting company. He 2014-2015, Brigadier General Todorov was the deputy director at the Missile Defense Agency 2014-2015, and . From 2011-2013 he oversaw Ground-Based Midcourse Defense Operations at United States Northern Command from 2011-2013.