Can a person with dual citizenship vote in both the countries.

A person who has a dual citizenship is a citizen of both
the countries in reference. So he/she has all the rights that a citizen of each of the
countries has. And this includes the right to vote as in a democratic
process.

As the concept of dual citizenship is not
recognized by all the nations and many forbid any foreign citizen from having a
citizenship of the country without denouncing their original citizenship, it is not
possible for people to be able to vote in all nations. But nations which allow dual
citizenship allow the person with the dual nationality to be part of the democratic
process just like an ordinary citizen of the nation.

A
classic example here is US Governor Arnold Schwarzenegger, who is a governor of a state
in the US and is also an Austrian citizen.