Frankly: the act of public service while already rich by any standard of the society should be volunteer. Are you worth more than a million dollars? Yeah, you get your travel reimbursed, maybe some meal vouchers. Because actively working to keep the country in order and serving the public? Your payment is warm fuzzies.
Do you not have a million dollars? Okay, you get travel reimbursed, maybe some meal vouchers, and... let's be generous: 1.5 times the average income. Oh, and all the warm fuzzies from making life better for hundreds of millions of people. You're welcome.
But hey, while we're dreaming: let's make summary execution the defacto punishement for violating your oath, and let's make the suspicion of it sufficient cause. Cause fear is the best reason to behave.