But this is not all: if we advert to the observations already made respecting the courts that subsist in the several states of the Union, and the different powers exercised by them, it will appear that there are no expressions more vague and indeterminate than those which have been employed to characterize that species of causes which it is intended shall be entitled to a trial by jury. In this state, the boundaries between actions at common law and actions of equitable jurisdiction, are ascertained in conformity to the rules which prevail in England upon that subject. In many of the other states the boundaries are less precise. In some of them every cause is to be tried in a court of common law, and upon that foundation every action may be considered as an action at common law, to be determined by a jury, if the parties, or either of them, choose it. Hence the same irregularity and confusion would be introduced by a compliance with this proposition, that I have already noticed as resulting from the regulation proposed by the Pennsylvania minority. In one state a cause would receive its determination from a jury, if the parties, or either of them, requested it; but in another state, a cause exactly similar to the other, must be decided without the intervention of a jury, because the state judicatories varied as to common-law jurisdiction.
It is obvious, therefore, that the Massachusetts proposition, upon this subject cannot operate as a general regulation, until some uniform plan, with respect to the limits of common-law and equitable jurisdictions, shall be adopted by the different states. To devise a plan of that kind is a task arduous in itself, and which it would require much time and reflection to mature. It would be extremely difficult, if not impossible, to suggest any general regulation that would be acceptable to all the states in the Union, or that would perfectly quadrate with the several state institutions.