Permanent Residence (a "green card") grants the right to live in, leave and reenter, and work in the U.S. It does not grant, for instance, the right to vote in U.S. elections. Permanent Residence may be deemed abandoned if the U.S. government believes that the permanent resident has not maintained sufficient ties to the U.S. to demonstrate intent to keep it. It can also be revoked if, for instance, the permanent resident commits certain crimes.
Citizenship includes all those rights, plus the right to vote and certain other rights. Citizenship cannot be deemed abandoned even if the citizen resides aborad for long periods of time without strong ties to the U.S. It can be taken away, but normally only if the naturalized citizen can be proven to have misrepresented something during the naturalization process (or does something which could also cause removal of citizenship to a U.S.-born citizen, such as fighting with a foreign army against the U.S.)
Citizenship includes all those rights, plus the right to vote and certain other rights. Citizenship cannot be deemed abandoned even if the citizen resides aborad for long periods of time without strong ties to the U.S. It can be taken away, but normally only if the naturalized citizen can be proven to have misrepresented something during the naturalization process (or does something which could also cause removal of citizenship to a U.S.-born citizen, such as fighting with a foreign army against the U.S.)
