If any law illustrates how wrongly decided South Dakota v. Dole was, then it's the Hatch Act. Under the Hatch Act, a state employee can't run for certain state elective offices. In other words, the federal government regulates who can run for state office. Wow.
How does this work in real life? A friend, who intends to run for the state senate, was offered a job as a prosecutor. He had to turn the job down because it would have been illegal for him to work as a state employee while running for state elective office. Officials in Washington, D.C., it seems, have some interest in ensuring that Arizona prevents prosecutors from running for office.
While there are likely good policy reasons to regulate state elections, why is the federal government involved? Certainly, Congress has the power under the Civil Rights Amendments to ensure that voting rights are not abridged. But why can Congress regulate state and local elections in this way? (I realize that this law is likely constitutional under South Dakota v. Dole, but putting aside Dole, where is the national interest?)
The Hatch Act illustrates why the Court needs to reinvigorate the Tenth Amendment. Congress should have the power to attach conditions to federal funds, but those conditions should be invalided when they reach intimate, and traditional, state functions. How far this doctrine should extend would be a tough question. (Nat'l League of Cities; San Antonio MTA). But whether the federal government should be able to regulate state elections (unrelated to the Civil Rights, and the 19th and 26th Amendments) is not a difficult issue.