Brian Russ has posted this draft on SSRN. Here is the abstract:

The question is straightforward: does California’s ban on campaign contributions from lobbyists violate the First Amendment? The answer is not straightforward. The purpose of this Comment is to assess the validity of California’s ban against the changes to campaign finance law since Chief Justice John Roberts’s appointment to the Court. The Chief Judge has authored several decisions that diverted the course of campaign finance law through constitutional interpretations that will likely overwhelm California’s justifications for the ban.

In 2000, California enacted Government Code § 85702, thereby barring lobbyists from making contributions to an elected state officer or candidate for state office if the lobbyist is registered to lobby the officer’s government agency. In 2001, the only time the question was litigated, the District Court for the Eastern District of California found the ban to be constitutional on First Amendment grounds. The decision was not appealed and remains the only case law on the ban. At the end of California’s 2015 legislative session, the state had nearly 1,800 registered lobbyists.

Questioning the vitality of the ban is important because unrestricted political speech is an indispensable element of democratic self-governance. If the ban were challenged today, the outcome may be markedly different. Since Chief Justice John Roberts joined the Supreme Court in 2005, campaign finance limitations have been dramatically struck down as unconstitutional. California’s ban was enacted near the end of the Rehnquist Court, where decisions like Austin and McConnell averred a broad threat of corporate influence in elections to uphold restrictions on the political speech of corporations. However, the Roberts Court overturned parts of Austin and McConnell in Citizens United and McCutcheon, downplaying the threat of potential corruption caused by corporate monies in elections. If litigated today, California’s ban on lobbyist campaign contributions would likely be held unconstitutional as an overbroad restriction that neither respects lobbyists’ personal political interests nor responds to threats of actual or perceived corruption.