For years and years, the left in the U.S. maintained that the right to keep and bear arms existed only under the auspices of a well regulated militia, which is tautological when you think about it.
(The reasons were explained pretty clearly in the majority opinion of D.C. vs Heller.)
To be fair, the Latin sentence structure of the Second Amendment is confusing to some people, so their position strikes me more as inaccurate / incorrect / untenable / erroneous than unconstitutional.
But that's just me