You have to admit there is a certain illogic to the notion that amending the Constitution to make a government obey a Constitution, that they already ignore, seems pointless.
For one thing, if 2/3 of the state legislatures actually got on board with this, presumably because they believed Fedzilla needed to be reined in constitutionally, then the 17th Amendment would be out, and those state legislatures would each appoint two senators who would follow the constitution.
Sure, that still leaves the House and the Presidency still potentially running afoul of the Constitution, but that was a possibility foreseen by the Founders, and their remedy was the Judiciary -- and note how disastrous that 17th Amendment was to the makeup of the Senate. Judicial confirmations would be much more sane if the senators were once again representing the interests of the states and not the popular will of the people.