Sovereign immunity is based on the ancient principle that the king is the source of justice so “the king can do no wrong.” Sovereign immunity ought to have been abolished back when we got rid of kings.
That’s only one reason behind the policy.
“The doctrine of sovereign immunity serves a multitude of purposes including, but not limited to, protecting the public purse. The additional purposes include providing for the smooth operation of government; eliminating the public inconvenience and danger possibly stemming from the reticence of officials to act; and preventing citizens from improperly influencing the conduct of governmental affairs through the threat or use of vexatious litigation.” Messina v. Burden, 228 Va. 301 (1984).