What is the test for equalization under the Fourteenth Amendment?

It merely requires that all persons subjected to such legislation shall be treated alike under like circumstances and conditions, both in the privilege conferred and the liabilities imposed. * * * Mr. Justice Field said in Mobile County v. Kimball, 102 U. S. 691 [26 L. Ed. 238], that this court is not a harbor in which can be found a refuge from ill-advised, unequal, and oppressive state legislation. And he observed in another case: It is hardly necessary to say that hardship, impolicy, or injustice of state laws is not necessarily an objection to their constitutional validity. * * * There is therefore no precise application of the rule of reasonableness of classification, and the rule of equality permits many practical inequalities. And necessarily so. In a classification for governmental purposes there cannot be an exact exclusion or inclusion of persons and things. Bearing these considerations in mind, we can solve the questions in controversy.'

Referring to the fourteenth amendment and the state Inheritance Tax Laws, the case of Campbell v. California, 200 U. S. 87, 95, 26 Sup. Ct. 182, 185 (50 L. Ed. 382), gave occasion for Mr. Justice White to say: