The fair market value of your car is 20 thousand dollars.
I see you driving it and like it--a lot--so I follow you and tell you I want to buy it. I offer you 20K.
You say `No'.
I say, `I'm taking it anyway. If you won't sign, I'll get a court Order.'
If I understand you, apparently neither of you have a problem with a private developer doing just that to the homeowners here, because it's "not stealing" and we can just vote out the offenders.
This is a fine point to keep in mind. The state (using this as the global term for national, regional, state, county, and local governments) has many, many other options other than eminent domain seizure for acquiring movable property (like cars) and there are plenty of sellers willing to compete in providing those items to the government (often at considerable discounts). Consequently, the seizure of personal property by exercise of eminent domain is a non-issue, since it is: 1) inefficient (it is always inefficient and expensive when courts and lawyers are involved) and 2) government doesn't (or at least shouldn't) really prefer one legal source of a particular item over another as long as the need items are supplied at a fair price.
However, in the case of real property, there is only one source for a specific plot of land and that is purchase from the current owner. When the owner refuses to sell at a fair market value price (either to the developer or the government - are there can be abuses here) and the intended use is deemed by the government to be in the public interest, the owner becomes subject to eminent domain proceedings by the government. The government must go to court and prove to the satisfaction of a (hopefully) impartial judge that the public interest is being served by the seizure and the judge must accept their arguments to rule favorably. The judge's ruling is subject to appeal (in this case, all the way to the Supreme Court). And even if the government is vindicated at the end of all the appeals, it must still pay fair market value for the property (which can lead to another round of court hearings).
In short, eminent domain is a LEGITIMATE government power to be should be carefully invoked only in those cases where it cannot negotiate a reasonable sale with the real property (real estate) owner and the intended use is really "in the public interest."
Having said that, your assumption that I have no problem with the current use of eminent domain by local governments is wide of the mark. If local government officials are personally profiting or receiving campaign donations because of decisions favoring developers, that's criminal corruption and they should be indicted and sent to jail. I don't believe assessments should be manipulated to drive property owners off their land nor should changes in zoning be used to destroy the market value of property. I believe (as I implied in my original posting) that if the state must take a piece of property through eminent domain proceedings, it should pay a penalty for trumping the reluctant owner's property rights by paying triple (or more)over the fair market value for the land. That will force the state to be very judicious as to what property it decides to incorporate into its projects. Finally, I believe you should use the electoral process and the ballot box to punish (or reward) public officials (including judges) to offend the public's wishes about how government power should be exercised. They will be a little less capricious in the exercise of power if they know they will be held accountable by the voters. (Thank you Arnold Schwarzenegger!)).