I would add the Great Depression Constitution. With changes in things like turning the Commerce Clause on its head that lead to cases like Wickard v. Filburn (http://en.wikipedia.org/wiki/Wickard_v._Filburn) I can't really say we're living under the same constitutional order as the post-antebellum one.
The Progressives also made some significant changes (popular election of Senators, income tax), but one can at least argue that was done through the system by the amendment process. By the time of FDR, only fig leafs were required (e.g. the effective ban on private ownership of machine guns through a $3,250 "tax" (in today's dollars, or "The switch in time that saved nine" (http://en.wikipedia.org/wiki/Switch_in_time_that_saved_nine )) ... during the Great Depression). Now, D.C. doesn't even bother with the fig leafs ... one might seriously question how much we really live under the rule of law today, but its pretty clear that's long been an issue (one could start with e.g. the frankly unconstitutional and very early Alien and Sedition Acts, although they didn't last very long).
Mexico is also a ... strange case to cite, when one party held power for more than 70 years starting in 1929 (http://en.wikipedia.org/wiki/Partido_Revolucionario_Instituc...) ... it's name, in English, is rather suggestive: "Institutional Revolutionary Party". That said, starting sometime around then didn't it/the party provide a fairly stable form of government, and most notably they were willing to give up power peacefully (more or less) fairly recently.
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I would add the Great Depression Constitution. With changes in things like turning the Commerce Clause on its head that lead to cases like Wickard v. Filburn (http://en.wikipedia.org/wiki/Wickard_v._Filburn) I can't really say we're living under the same constitutional order as the post-antebellum one.
The Progressives also made some significant changes (popular election of Senators, income tax), but one can at least argue that was done through the system by the amendment process. By the time of FDR, only fig leafs were required (e.g. the effective ban on private ownership of machine guns through a $3,250 "tax" (in today's dollars, or "The switch in time that saved nine" (http://en.wikipedia.org/wiki/Switch_in_time_that_saved_nine )) ... during the Great Depression). Now, D.C. doesn't even bother with the fig leafs ... one might seriously question how much we really live under the rule of law today, but its pretty clear that's long been an issue (one could start with e.g. the frankly unconstitutional and very early Alien and Sedition Acts, although they didn't last very long).
Mexico is also a ... strange case to cite, when one party held power for more than 70 years starting in 1929 (http://en.wikipedia.org/wiki/Partido_Revolucionario_Instituc...) ... it's name, in English, is rather suggestive: "Institutional Revolutionary Party". That said, starting sometime around then didn't it/the party provide a fairly stable form of government, and most notably they were willing to give up power peacefully (more or less) fairly recently.