The power to destroy neighborhoods to build a bridge, the power to punish people for their beliefs. FBI director J. Edgar Hoover and New York City Parks and Transportation head Robert Moses were both accused of taking on destructive projects, and both were accused of intimidating politicians in order to stay in power. In _The Power Broker_, Robert Moses is portrayed as an almost tragic figure in his last years, unable to understand why people were not more appreciative of the good work he had done.
It is thanks to Moses that New York state has many of its parks, and some of Moses early highway projects were quite beneficial. It is just as easy to forget that Hoover, when he started at what was not yet called the FBI, was almost single handedly responsible for making reforms that helped everyone, except for the drunks he fired and the bad guys he caught. Okay, _he_ didn't catch the bad guys personally, the Carpas publicity stunt not withstanding. But in his early years as director, Hoover improved the morale and efficiency of those who did (occasionally) face literal gunfire.
I'm suggesting that late career mistakes can overshadow past accomplishments, and that power corrupts. There is a good reason that after Moses, the Bridge and Tunnel Admin was separated from the MTA, and both, of course, from the Parks Department. Moses was in power for decades, Hoover for about half a century. There is a reason that the FBI director now serves a maximum of, I think, ten years.
Is anyone capable of maintaining power for that long without abusing it more as time passes?