But I don't agree with Prof. Zywicki. At least some state legislatures were very corrupted at the end of the 19th Century, which had a direct affect on the election of US Senators. The Progressive movement may not have passed its entire agenda, but many states did get recall and initiative laws passed at that time.
As for the growth of the federal government, I think WWI and the income tax were more responsible than the Seventeenth Amendment.
Is it better now that all of the elections of Senators is corrupted by campaign money? Is it easier for special interests to bribe 100 men or 5,000 men?