How can you "keep the local government in check"?

I guess "keep in check" means "restrain." But how can you "keep the local government in check "? The govenment acts according to laws!

Context:

In many places in the US you pay taxes on the property but there are 'homesteader' rights. This is where the elderly get tax discounts and other benefits to lower their overall tax bill.

Very few places in the US will take your property for being 1 year behind on taxes any more. I know in Ohio there are people that are 10-15 years behind, with the information being published in the paper yearly. You can buy the property for taxes but they have the right to fix tax bill within 30 day, and you assume all debts assigned to the property.

The system works in the US as long as you keep the local government in check and stop them from nickle and dimming you for everything that comes up since it 'will only cost a home owner of a $100,000 a few dollars a year', but everybody wants there money and it is never enough.