The right to vote in the US.
The citizens of the District of Columbia.
One responsibility that is only for US citizens is the right to vote in federal elections. Only US citizens are eligible to participate in the democratic process by voting for their representatives in the federal government. Non-citizens, including permanent residents, do not have this right.
ONLY THE CITIZENS CAN VOTE!
Yes they are
Only a native born citizen can become the President of the US.
The people that started the US believed that people had a right to be judged by their fellow citizens, and not by the government.
Treated differently in what regard? Many US citizens would argue that, in some respects, non-citizens are even more privileged than they are. In many cases the only privilege that a non-US-citizen doesn't enjoy is the right to vote in a US election.
Citizens of the District of Columbia were given the right to vote on March 29,1961 when the 23rd amendment to the Constitution was ratified.
Freedom of speech/religion
US citizens.
Not only can they, but companies receiving money from the 2008/09 Stimulus Package MUST hire US citizens if they have laid off US citizens.
One responsibility that is only for US citizens is holding the office of the President of the United States. A person must be born in the US to be president. Voting is another thing that only citizens can do.