Answering a question for an MTV viewer, Barack Obama expressed opposition to California's Proposition 8, a state constitutional amendment on the ballot that would ban gay marriage. Obama repeated that he believed that marriage is "between a man and a woman" but that ban of gay marriage was "unnecessary."

The full interview is set to air at 9 p.m. ET on MTV. More details are here.

This video is from, broadcast November 1, 2008.

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