This is very true, the States have allowed this to happen. But Sowell's article is not about State's power, so he didn't leave it out. Nonetheless, you are correct. I believe one of the biggest Constitutional errors was the States turning the election of Senators to a public election. The State legislature selecting Senators was a balance of power for the States to ensure the State voice was heard in Congress, and prevent emotional, irrational overthrow of government by either the government or the people. The States have no voice other than to use their legislatures, and they aren't doing that either.