Well, if you are looking for a specific example, I suppose one could argue that many of America's extremely controversial SDI (Strategic Defense Initiative - nicknamed "Star Wars") ballistic missile defense shield programs were a serious waste of resources, seeing as how the much-touted systems were never deployed operationally.

On one side of the coin, SDI cost the US taxpayers a simply absurd amount of money that resulted in no viable space-based ballistic missile defense shield ever being produced. Since 1983 when the Reagan Administration initiated the SDI program, well over $200 billion dollars was spent on SDI research and development (some estimates put the figure significantly higher than that due to military and intelligence agencies use of "black budget" accounting that could have helped hide the true overall cost figures).

Of course, some of that R&D money spent on SDI was not totally in vain though, as there was at least some trickle-down tech and knowledge gained from those never-realized and very expensive ballistic missile shield programs that subsequently made its way into the US military and intelligence agencies arsenal of space-based intel gathering and weapons systems tricks. Still though, it was a hell of a lot of money and resources spent over considerably time with comparatively very little in the hardware department to show for the effort.

While the space-based missile shield was never deployed, some historians have claimed that the SDI program, with its extremely high cost and the political issues it caused within the USSR, may be considered to have contributed, at least in part, to the eventual fall of the Soviet Union, making it a worthwhile expense overall for the US taxpayers. The possible contribution claims came mainly in the form of saying that SDI forced the Soviets to meet America's plans by also spending a hell of a lot of rubles and R&D resources on trying to come up with ways to counter or defeat the USA's impressive proposed space-based ballistic missile shield - money that the USSR did not really have and could certainly have used elsewhere to help their failing economy during the later half of the 1980s. In October of 1986, in an address to the Soviet Politburo, Mikhail Gorbachev, the USSR's Head of State, said this of the economic threat that SDI posed to his nation "[W]e will be pulled into an arms race that is beyond our capabilities, and we will lose it because we are at the limit of our capabilities. … If the new round [of an arms race] begins, the pressures on our economy will be unbelievable."

Here is a rather long paper that does a good job of dissecting the Soviet response to America's SDI programs, though this paper does not really agree with the idea that SDI played a large contributing role in ending the Cold War as some may think. It is a good read though, and does discuss some of the insurmountable technological hurdles that resulted in America failing to see their SDI plans ever be realized or actually put into service.

What is certain though is that the USA indeed spent a lot of money and R&D resources on the SDI space-based ballistic missile defense programs, with not much to show in terms of positive results coming from those very expensive and time-consuming efforts that could ever really justify the cost.