Which of the following is a right only for United States citizens?

Voting in federal elections is a right that is exclusively granted to United States citizens. This means that only individuals who have gone through the process of naturalization or were born as citizens can participate in national elections, such as those for the President, members of Congress, and other federal offices. This restriction reflects the principle that voting is a fundamental aspect of citizenship and an expression of one's stake in the governance of the country.

In contrast, the other rights listed—freedom of speech, the right to a public trial, and freedom to assemble—are rights that are extended to all individuals within the United States, regardless of their citizenship status. These rights are protected under the First Amendment and other constitutional provisions, ensuring that everyone can express themselves, seek a fair trial, and gather peacefully, thus fostering a democratic society.