When accused of targeting Menendez for criticizing Obama, their defense was that he had been under investigation for several years.
Which only proves the point. They knew about him for years. As long as he stayed in line, he was teflon. The moment he spoke out of turn, though, the hammer fell.
It's especially useful when the men are not so innocent. The dirty politician is allowed to be dirty as long as he works for the team. But, if he steps out of line, you can crush him. Everyone can be crushed at any time. Everyone is a law-breaker. That's the goal. Then everyone lives in fear.