<P> With the protection of mission staff from prosecution for violating civil and criminal laws, depending on rank, under Articles 41 and 42 of the Vienna Convention, they are bound to respect national laws and regulations . Breaches of these articles can lead to a persona non grata declaration being used to punish erring staff . It is also used to expel diplomats suspected of espionage (described as "activities incompatible with diplomatic status") or any overt criminal act such as drug trafficking . The declaration may also be a symbolic indication of displeasure . </P> <P> So - called "tit for tat" exchanges have occurred (whereby ambassadors of countries involved in a dispute each expel the ambassador of the other country), notably during the Cold War . A notable occurrence outside of the Cold War was an exchange between the United States and Ecuador in 2011: the Ecuadorian government expelled the United States ambassador, as a result of diplomatic cables leaking (WikiLeaks), the United States responded by expelling the Ecuadorian ambassador . </P> <Table> <Tr> <Td> </Td> <Td> This section does not cite any sources . Please help improve this section by adding citations to reliable sources . Unsourced material may be challenged and removed . (March 2015) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This section does not cite any sources . Please help improve this section by adding citations to reliable sources . Unsourced material may be challenged and removed . (March 2015) (Learn how and when to remove this template message) </Td> </Tr>

Why might a president consider a country persona non grata