As a general rule, both the United States and the Commonwealth of Virginia enjoy sovereign immunity, which shields the government entities and their agencies from defamation lawsuits as well as most other types of litigation. The law becomes trickier when applied to the employees of those governments. Federal employees are immune from defamation claims based on things they said while acting within the scope of their employment. Those who work for the Commonwealth of Virginia, on the other hand, or one of its counties, cities, or towns, don't have it so easy. Virginia employees do enjoy some degree of sovereign immunity for their actions, but--with limited exceptions--the protection they are afforded is less than the absolute protection federal employees receive. Like federal employees, state and local employees must be acting within the scope of their employment to be potentially entitled to claim immunity, but state employees need to meet additional criteria before they will be granted immunity.
The Virginia Supreme Court has described sovereign immunity as "a rule of social policy, which protects the state from burdensome interference with the performance of its governmental functions and preserves its control over state funds, property, and instrumentalities." This rule of social policy is essentially based on the following goals: (1) to protect the "public purse" (i.e., to preserve tax dollars), (2) to address the concern that officials might be unwilling to carry out their public duties if they lived in constant fear of being sued, (3) to encourage citizens to take public jobs, and (4) to permit the orderly administration of government by discouraging improper influence through vexatious litigation. (See Messina v. Burden, 228 Va. 301, 308 (1984)). Consideration of these policies is what guided the Virginia courts to develop a rule affording immunity to some state and local employees but not others.