“ To say that no one who was a taxpayer in a city or town could act in imposing an assessment upon property therein is to say that the legislature is wholly without power, by reason of the Federal Constitution, to constitute a tribunal to make an assessment where such tribunal is composed of taxpayers in the city or town. This we do not believe. It must frequently happen that a board of assessors for a city, to assess all property for general taxation, will be composed of men who themselves own property in the city and assess the same for purposes of such taxation. ”

“ Whether a judgment obtained in a case like this, where two members of a general board created by statute for the purpose of making it had some interest in some of the property subject to the assessment, was a void or voidable judgment, is a proper question for the state court to decide. A state court has the right to place its own construction upon its own judgments, and where, as in a case like this, it holds that the judgment is not void, and that it cannot be attacked collaterally, we ought to follow that determination. ”

“ Due process of law is afforded where there is opportunity to be heard before the body which is to make the assessment, and the legislature of a state may provide that such hearing shall be conclusive so far as the Federal Constitution is concerned. ”