When is a plaintiff unable to pursue a lawsuit against a foreign government?

A plaintiff is unable to pursue a lawsuit against a foreign government primarily when there is no waiver of sovereign immunity. Sovereign immunity is a legal doctrine that shields foreign governments from being sued in other countries' courts unless they consent to the suit or if an exception applies under applicable law, such as the Foreign Sovereign Immunities Act (FSIA) in the United States.

In many legal systems, foreign governments can only be held liable if they explicitly waive their immunity regarding a specific claim. Without such a waiver, the courts typically lack jurisdiction over the matter. Therefore, if a foreign government has not consented to be sued, the lawsuit cannot proceed.

While personal grievances, diplomatic protection, and state secrets may influence the dynamics of a case, they do not directly address the fundamental principle of sovereign immunity and whether a court can exercise jurisdiction over a foreign government. Thus, without a waiver of sovereign immunity, a plaintiff's attempt to pursue a lawsuit against a foreign government will be unsuccessful.