for to a certain
extent both the Governments are sovereign and independent of each other,
and in that form it is possible, though not probable, that opposition
might be made. To each limitations are prescribed, and should a contest
rise between them respecting their rights and the people sustain it with
anything like an equal division of numbers the worst consequences might
ensue.

It may be urged that the opposition suggested by the owner of the
land or by the States individually may be avoided by a satisfactory
arrangement with the parties. But a suppression of opposition in that
way is no proof of a right in Congress, nor could it, if confined to
that limit, remove all the impediments to the exercise of the power.
It is not sufficient that Congress may by the command and application
of the public revenue purchase the soil, and thus silence that class of
individuals, or by the accommodation afforded to individual States put
down opposition on their part. Congress must be able rightfully to
control all opposition or they can not carry the system into effect.
Cases would inevitably occur to put the right to the test. The work must
be preserved from injury, tolls must be collected, offenders must be
punished. With these culprits no bargain can be made. When brought
to trial they must deny the validity of the law, and that plea being
sustained all claim to the right ceases.

If the United States possess this power, it must be either because it
has been specifically granted or that it is incidental and necessary
to carry into effect some specific grant. The advocates for the power
derive it from the following sources: First, the right to establish
post-offices and post-roads; second, to declare war; third, to regulate
commerce among the several States; fourth, from the power to pay the
debts and provide for the common defense and general welfare of the
United States; fifth, from the power to make all laws necessary and
proper for carrying into execution all the powers vested by the
Constitution in the Government of the United States or in any department
or officer thereof; sixth and lastly, from the power to dispose of and
make all needful rules and regulations respecting the territory and
other property of the United States. It is to be observed that there
is but little accord among the advocates for this power as to the
particular source from whence it is derived. They all agree, however,
in ascribing it to some one o