It may make any provision that it pleases, but it must be done by the Legislature.

It must be the legislative body which gives the power that is to settle the mode of action.

Now what are the facts in this case?
There was no provision whatever made by the Legislature of the State of New Jersey as to the mode in which the senator should be chosen.

The legislative action which authorized the convention was perfectly silent upon that subject.

What then had the Legislature the right to conclude?
Was it not this, and this only ?--that when it authorized a body other than itself, though constituted of the same members, a convention to choose a senator, that body must proceed in the choice of a senator according to the universally received Parliamentary and common law upon the subject of elections.