Wouldn’t they still have incentives to aid parties who promise to repay them once their term is up?
Only if they can trust the promise; once their term is up, the parties have little real incentive to stick to their promise, after all.
There will be an incentive to aid people who immediately donate a great big chunk of money to the State, as that money will be shared out among the ministers at the end of their term in any case; but the incentive only works, there, if the great big chunk of money is more than the state would obtain by other means.
Only if they can trust the promise; once their term is up, the parties have little real incentive to stick to their promise, after all.
There will be an incentive to aid people who immediately donate a great big chunk of money to the State, as that money will be shared out among the ministers at the end of their term in any case; but the incentive only works, there, if the great big chunk of money is more than the state would obtain by other means.
In iterated games, defection has its price.
I see your point and, on further thought, acknowledge it as correct.