I don't think anyone as savvy and successful as Keith Alexander wants to bake J. Edgar Hoover's image into their legacy.

http://jontaplin.com/2008/03/11/eliot-spitzer-the-nsa/

"I’ve been tough on Spitzer, but we can’t forget that the reason he got in trouble was because of the new NSA domestic surveillance apparatus that was so brilliantly depicted in the Wall Street Journal yesterday. Here’s the Lede.

  Five years ago, Congress killed an experimental Pentagon 
  anti-terrorism program meant to vacuum up electronic data 
  about people in the U.S. to search for suspicious 
  patterns. Opponents called it too broad an intrusion on 
  Americans’ privacy, even after the Sept. 11 terrorist 
  attacks.

  But the data-sifting effort didn’t disappear. The National 
  Security Agency, once confined to foreign surveillance, 
  has been building essentially the same system.

Spitzer was what the data-mining experts at the NSA call a PEP–a politically exposed person. Banks now monitor PEP’s money wiring activities figuring they are classic targets of blackmail or bribery. Spitzer got caught in the data mining screen. I know people will probably say that even Mukasey had to sign off on an investigation as explosive as this. Spitzer was a self-detructive idiot, but at the end of the day, we have to realize that nobody has any privacy anymore."

Many people consider legacies to be overrated. Reputation while still alive and kicking is something that concerns just about everybody though.

I wrote something about how ubiquitous surveillance can be used to blackmail anyone about a month ago:

https://news.ycombinator.com/item?id=5974734