Earlier quoted context omitted.
If you think about it, it's a bit odd that there are so few mercenaries in this day and age. When you look back on history then from what I can tell, mercenaries were much more common.
It's not an accident. Nation-states spent an awful lot of time and money building up professional armies precisely because they had long experience depending on mercenaries. They knew that there were only two ways depending on mercenaries ever ended: either the country couldn't pay the mercenaries enough, in which case they sold them out to a higher bidder; or it could , in which case the mercenaries would eventually…
To stop this problems and other problems, like people in places like the SEC immediately going to work for companies under SEC investigation when they leave, and other revolving doors, it would probably be worth paying higher-level people (special forces operatives, District Attorneys, EPA commissioners etc.) a much higher level of pension that starts paying immediately after leaving the job, contingent on their lifetime disbarment from certain kinds of employment. If the person wishes to go work in such a position, that money needs to be paid back immediately.
It won't stop everyone, but done correctly it could stem the most egregious of revolving doors.