Legal Question in Tax Law in Illinois

What makes taxation legal? Congressional statutes with respect to the Federal government, and Illinois General Assembly legislation with respect to Illinois tax. Barring a constitutional defect of some sort in the statute, if Congress or the General Assembly says it's legal, it is. The beauty of the taxation system is that taxes are stacked by as many instrumentalities of government as can persuade the populace that they need a piece of the transaction. Thus, county and municipal taxes can be added (subject to enabling legislation and constitutionality).