Under California law, registered lobbyists are prohibited from giving campaign contributions to state candidates. The purpose of this prohibition is rather straightforward. Contributions from those overtly seeking to influence elected officials could lead to corruption, or at least the appearance of corruption. Simply put, such contributions are or seem particularly unseemly.
However, under federal law, lobbyists are free to give to federal candidates. Federal law controls federal races, while state law dictates the permissible behavior for state races. Therefore, when state elected officials run for federal office, the same lobbyists prohibited from giving to state campaigns are free to give to federal ones. It strains common sense to think that state elected officials would be thankful for contributions to their state campaigns, but not as grateful to lobbyists for contributions in their federal campaigns.
Finish reading this article on KCET.