Hard to say.
On the good side, most new military tech is created by us, and then stolen by everybody else both "allies" and enemies. So we have been a "step" ahead in that regard for several decades. Since it takes a while to steal and reverse engineer our weapon systems and "create" their own versions. Most of the time those copies are inferior due to material or tech problems they can't engineer their way out of. For example the Soviet Union never had micro-computer tech or the best high strength metals (like steel). So their copies were often heavier or couldn't do things that required micro computers. Thought they got pretty good at making copies of Intel computer processors, though towards the end I believe they just bought computers on the open world market.
So if we stop developing new tech, it will slow overall development as other places will have to do more R&D. Things may not develop much and current tech may be relevant much longer. However if another place starts developing on a larger scale, we would be locked out of new tech and it may be very difficult to get back to the top.
On the bad side, our military is very dependent on tech. And that is growing as people like Obama want fewer and fewer actual people in military uniforms. Will our military be able to do anything when the tech isn't working? Hard to say, most of today's rank and file people probably could, in 15 years, when those people have been replaced by Obama bots, not too good. The military has become far less attractive to our "warrior class" in the last decade due to the policies of the current government. The next president will have a HR problem to deal with.
And we no longer meet the enemy on a battlefield and we can't really "invade" a place anymore. This is a big one. War is irregular, guerrilla style (ironically developed by us during our revolution) no real "front" lines (Korea being the last war with clear front lines) and many times against an enemy that isn't a nation with defined borders. Armies are always fighting the last war like in all of history, and it takes time for that rational to go away during the current conflict. If your like the French, you don't like change, and when you finally do it, you do the wrong thing.
No one is stupid enough to take us on head on. Not even the Chinese would even try that. It would be suicide. At the moment we seem to be the "suicidal" nation. Maybe the history books will be writing stories about us someday, wondering why we committed societal suicide, like how we do with kamikaze pilots of WWII today. (Interesting note, the Germans had some Kamikaze pilots too, toward the end, though, most of those pilots did try to bail out and survive the attack).
Guerrilla type war wears us down, in many ways as shown by Vietnam, Iraq and Afghanistan. It takes too long making public opinion turn on it. It's hell on the solders as they are exposed to terror attacks even in "secure" locations. They have problems with who is the enemy, as they aren't wearing uniforms most of the time. Often they don't know until some local they may have known for months or years blows up taking a bunch of people with them.
We may be able to attack and destroy our enemies without warning with our expensive weapon systems, but terrorists can too. Most of the time they are using little tech in the process. We are far easier to track then they will ever be.
I don't know where I read it, but the terror attacks on the trade towers and the pentagon cost less then $600,000 for the terrorists organizations that planned them. As you can see, it doesn't take much money to make a huge mess.
