Sovereign immunity is a legal concept which dates back to the Middle Ages. Under sovereign immunity, the sovereign cannot be held accountable in tort suits, under the argument that because the sovereign makes the law, it is impossible for the sovereign to commit civil wrongs. This concept has been integrated into the legal systems of a number of nations around the world, although it is controversial in some regions.
This concept was developed, unsurprisingly, by literal sovereigns who wanted to protect themselves from suit by the people. It was often used as a tool for suppression, by making it difficult for citizens to find redress when civil wrongs were committed by the government. In modern uses, however, it refers to a sovereign in the sense of the government. Nations governments are considered protected under sovereign immunity, but individual representatives of the government can still be held liable for civil wrongs they commit. Being the President or Prime Minister of a country, for example, does not exempt one from liability.
Originally, this protection from liability was used as a blanket shield, limiting opportunities for citizens to sue the government. Over time, the concept evolved. The government can waive immunity or consent to a specific suit, and several governments have actually passed sweeping laws which waive immunity for most suits, providing citizens with the right to sue the government in civil cases. When the government is brought to court, a representative appears on behalf of the government during the trial.
Different nations apply sovereign immunity laws differently, and may have protections at lesser levels of government as well. Citizens in nations which allow suits can use suits to challenge the law, to force the government to address problems it is responsible for, and for other reasons. Such suits often involve multiple citizens who are presented by very skilled lawyers.
Because sovereign immunity is under increasing challenge in many areas of the world, when governments rely on this legal principle to avoid suit, they sometimes attract the ire of their populace. Citizens may accuse the government of hiding behind the sovereign immunity clause, rather than being willing to face its day in court. This can be especially controversial in contested cases where citizens may feel like they are being silenced or ignored by the government. Sometimes governments may have good reasons for not wanting to go to court, such as concerns about national security, but this reasoning is not always accepted by angry citizens.