I partially disagree though with the last bit about the Repeal Amendment. I don't believe it would have any affect on a state's ability to interpose and nullify an unconstitutional Federal law. I think that would just happen anyway regardless and said law would just not be recognized and obeyed/implemented in that state or collection of states <2/3 majority. I feel the Repeal Amendment is unnecessary to combat unconstitutional Federal acts.

However, I do agree and worry about how the Repeal Amendment could be used to repeal acts of Congress which are perfectly constitutional and within its bounds, acts which, I acknowledge, are few and far between. If the minority still found a constitutional Federal law to be favorable, they would be unable to enact it at the state level if repealed by a 2/3 majority because the power to do so has already been delegated to Congress. 2/3 of the states cannot be allowed to dictate constitutional Federal laws in such a way. On this I believe the warning about becoming more democratic and less republican (as in form of government; I am not referring to the Party, and yes, I do mean to use that term in the singular) is totally warranted.

Article III, Section 3 states, in part: “Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort.”

Note the reference to the United States as “them” and “their.”

Amendment Eleven states: “The Judicial power of the United States shall not be construed to extend to any suit in law or equity, commenced or prosecuted against one of the United States by Citizens of another State, or by Citizens or Subjects of any Foreign State.”

Note the use of the words “one of the United States.”

The 1850 admission document for California states that it “shall be one, and is hereby declared to be one, of the United States of America.”

“Be it Enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That the State of California shall be one, and is hereby declared to be one, of the United States of America, and admitted into the Union on an equal footing with the original States in all respects whatever.”

Alexander Hamilton in Federalist Essay No. 83:

"The United States, in their united or collective capacity, are the OBJECT to which all general provisions in the Constitution must necessarily be construed to refer." [Emphasis not added]

Note the omission of "the people" from Hamilton's statement.

If the term United States, as used in the Constitution, refers to the States collectively, then the government of the States collectively (Government of the United States) is the _______s' government.

Upshur made the following prediction in his 1840 book:

"So far as (the federal) government is concerned, I venture to predict that it will become absolute and irresponsible, precisely in proportion as the rights of the States shall cease to be respected, and their authority to interpose for the correction of federal abuses shall be denied and overthrown. It should be the object of every patriot in the United States to encourage a high respect for the State governments. The people should be taught to regard them as their greatest interest, and as the first objects of their duty and affection. Maintained in their just rights and powers, they form the true balance-wheel, the only effectual check on federal encroachments.
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The danger is, not that the States will interpose too often, but that they will rather submit to federal usurpations, than incur the risk of embarrassing that government, by any attempts to check and control it."

Looks like Upshur was looking into his crystal ball when he wrote these words.