State and federal courts have recognized that individuals acting in a legislative capacity are immune from liability for those actions. The legislative immunity doctrine is deeply embedded in Anglo American law, serving to encourage free and open debate.

The legislative immunity doctrine is not intended to protect individual legislators, but instead serves the public's interests. Because the immunity doctrine serves important public purposes, courts have affirmed that the doctrine generally shields legislative actors not only from liability, but also from being required to testify about their legislative activities.

The threat of liability can create perverse incentives that operate to inhibit officials in the proper performance of their duties. In many contexts, government officials are expected to make decisions that are impartial or imaginative, and that above all are informed by considerations other than the personal interests of the decisionmaker.

Because government officials are engaged by definition in governing, their decisions will often have adverse effects on other persons. When officials are threatened with personal liability for acts taken pursuant to their official duties, they may well be induced to act with an excess of caution or otherwise to skew their decisions in ways that result in less than full fidelity to the objective and independent criteria that ought to guide their conduct.

Courts have extended the legislative immunity doctrine beyond federal and state legislators to other individuals performing legitimate legislative functions. And when a person acts as a legislator, legislative immunity extends to the legislator's aides because their assistance is so critical to the legislator's performance that they must be treated as the latter's alter egos to avoid thwarting the purposes legislative immunity furthers.

In California, as in other states, the legislative immunity doctrine is recognized by both state and federal courts. This doctrine provides immunity to individuals acting in a legislative capacity, shielding them from liability for their legislative actions. The purpose of this immunity is not to protect the legislators themselves but to serve the public interest by promoting free and open debate without the fear of subsequent legal action. Legislative immunity ensures that government officials can perform their duties without the inhibition that potential personal liability might cause. This encourages decisions that are impartial, imaginative, and informed by public interest rather than personal consequences. In California, the doctrine has been extended to cover not only elected legislators but also other individuals who perform legislative functions, including legislative aides. These aides are considered integral to the legislative process, and thus are provided the same immunity to ensure the legislative function is not impeded.