This point can be better illustrated by a case which happened some years ago in one of the states.

A foreigner, who was the subject of a European country, was attacked by a mob, and his property destroyed.

He laid his complaint before the local authorities, but it appeared that he could not obtain the redress he sought.

His consul did all he could for him by appealing to the local authorities, but without success; finally the matter was reported to his ambassador in Washington, who immediately interested himself in the affair and brought it before the Secretary of State.

The Secretary, after going into the facts of the case, said that all he could do was to write to the Governor of that state and request him to take the matter up, but the Governor, for some reason or other, did not take any such action as would have given satisfactory redress to the foreigner.
His ambassador made frequent appeals to the Secretary of State, but the Secretary was powerless, as the Constitution does not empower the Federal Government to interfere in state matters.