This first became glaringly apparent during the Republican congressional reign of the 1990s. The committees of oversight spent so much time investigating 'Whitewater' and whether President Clinton had either murdered various members of his cabinet or slept with various interns that little actual oversight and investigations actually happened. Some of this is simply because Republicans -- not all but a lot of the office-holding class -- just don't believe in government at all and this isn't particularly interested in making it better.
I don't remember. I think it was an article in the Washington Monthly. But there was a great article either in the late 90s or early in the last decade that laid all of this out.
In any case, this all brings me to "Benghazi". At the moment the 'investigation' appears set to resolve entirely on whether the White House briefly focused on a paramilitary attack arising out of a spontaneous demonstration as opposed to a paramilitary attack that was planned in advance without any demonstration happening. Also, why the attackers were at first called "extremists" as opposed to identified as "al Qaida." In other words, the investigation lives entirely within the assumption that the White House was involved in a 'coverup' because the White House wanted to keep alive the idea that al Qaida was on the run in the aftermath of the bin Laden killing and that the attack on a facility in Libya by local militants (who might have adopted the name 'al Qaida' or had ties to someone else tied to al Qaida) who would turn the whole presidential election upside down.
Imagine for a moment a different kind of investigation. What sort of security failures were involved in letting a US Ambassador get killed for the first time in 30 years? Not just any country but one that has been near the forefront of the US foreign policy agenda in the last two years. Whoever did what, the President is responsible for what happens on his watch. And when an Ambassador gets killed in the field, that's a big failure by definition. Examining what's happening could and probably would lead to some embarrassing lapses. More importantly, it might lead to improvements in how we operate in the future and prevent or limit the possibility of similar tragedies.
In other words, mounting investigations that simply dance on the margins of the conspiracies coming out of Newsmax and Fox News doesn't just lead to more nonsense gas being emitted into the politico-cultural atmosphere of the United States. It leaves likely untouched the kind of screwups we really should know about and need to correct.
I don't pretend for a second that Republicans are the only ones responsible for highly politicized investigations. But the competition isn't even close for misdirecting the oversight process into freakshow conspiracy theories. From the good old days of Rep. Dan Burton discharging a handgun into the head of a pig corpse to get to the bottom of the Vince Foster 'murder' mystery into the whackjob carnival over Benghazi today, the GOP wins this one with flying colors.