Article 4, Section 4
Joseph Story, Commentaries on the Constitution 3:§§ 1808, 18191833
§ 1808. The want of a provison of this nature was felt, as a capital defect in the plan of the confederation, as it might in its consequences endanger, if not overthrow, the Union. Without a guaranty, the assistance to be derived from the national government in repelling domestic dangers, which might threaten the existence of the state constitutions, could not be demanded, as a right, from the national government. Usurpation might raise its standard, and trample upon the liberties of the people, while the national government could legally do nothing more, than behold the encroachments with indignation and regret. A successful faction might erect a tyranny on the ruins of order and law; while no succour could be constitutionally afforded by the Union to the friends and supporters of the government. But this is not all. The destruction of the national government itself, or of neighbouring states, might result from a successful rebellion in a single state. Who can determine, what would have been the issue, if the insurrection in Massachusetts, in 1787, had been successful, and the malecontents had been headed by a Caesar or a Cromwell? If a despotic or monarchical government were established in one state, it would bring on the ruin of the whole republic. Montesquieu has acutely remarked, that confederated governments should be formed only between states, whose form of government is not only similar, but also republican.
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§ 1819. It may not be amiss further to observe, (in the language of another commentator,) that every pretext for intermeddling with the domestic concerns of any state, under colour of protecting it against domestic violence, is taken away by that part of the provision, which renders an application from the legislature, or executive authority of the state endangered necessary to be made to the general government, before its interference can be at all proper. On the other hand, this article becomes an immense acquisition of strength, and additional force to the aid of any state government, in case of an internal rebellion, or insurrection against its authority. The southern states, being more peculiarly open to danger from this quarter, ought (he adds) to be particularly tenacious of a constitution, from which they may derive such assistance in the most critical periods.
The Founders' Constitution
Volume 4, Article 4, Section 4, Document 14
The University of Chicago Press
Story, Joseph. Commentaries on the Constitution of the United States. 3 vols. Boston, 1833.
Easy to print version.