An assassination program like this more or less defies the concept of 'ideas based on merit.'
Participating in this marketplace would be somewhat like voting, except it would have a tangible effect.
But a marketplace for violence is just as bad or even worse than the implicit violence of the state in my opinion. While I believe that sometimes violence might be necessary to oppose tyranny, I don't know that I trust the 'justness' of a system which presumes anyone employed by the state should find themselves subject to that kind of threat. Eventually (inevitably) it would wind up being used as a tool for political and ethnic genocide. Or petty crime.