The “American experiment” was federalism.
The Dobbs decision only returns the issue of abortion to the state legislatures. This is perfectly consistent with federalism and republicanism. Liberty is self government in your sovereign state. Women still have the right to engage in human sacrifice in New York and California.
Progressivism emerged in the early 20th century. The goal of Progressivism is to strip states and local communities of the power of self government and empower an omnipotent ruling class of technocrats, bureaucrats and experts – armed with the knowledge of social science and the conventional wisdom among PMCs – to solve social problems like, say, racial inequality or climate change.
Yes, these two ideas have always been in extreme tension. Progressives only believe in federalism when it suits them. They are fine with using the Supreme Court as a battering ram to impose sweeping social revolutions on the rest of the country – forced integration, federal control of state elections, interracial marriage, abortion and gay marriage to name just a few of their worst projects. They are only crying foul now that their instrument has been lost to the other side and turned against them.
This wasn’t supposed to happen. History itself was on their side. It was inevitable that the whole world from Alabama to the Donbas would be remade in their image. The “American experiment” itself has failed, which is conflated here with 20th century Progressivism, because of the loss of abortion rights.