When they run on a certain platform, make the platform an agreement with the people. Make it a binding agreement that they MUST fulfill if they are elected.
If they don't do their platform agreement in a timely manner, execution. The only way to save themselves from execution is when they work their hardest to accomplish the things in their platform contract, but are hindered every step of the way by other politicians in government. If this is what happened, life in prison without parole.
If an elected leader gets removed from office for not doing his platform contract, then the person who takes his place - like the vice president taking over for an executed president - has the same requirements to fulfill the platform agreement of the person whose place he took over. If he doesn't do it, then execution for him, too. His only option is to resign from the position, but then he gets life in prison as well.
Everybody who takes over when somebody gets executed out of office, must fulfill the agreement that the people elected in the first place. If they don't, execution or life in prison.
Let's straighten these governments out once and for all.