Iran leads with 32 percent of respondents listing the Middle Eastern country as the United States' top enemy. That number is up from 25 percent in 2011, and Iran has topped the list for the past five surveys since 2005.
Gallup cites Iran's continued public announcements of its growing nuclear capabilities, threatening Israel and the possibility that it could disrupt the flow of oil out of the Middle East as contributing factors to America's negative view.
Late last week, a bipartisan coalition of senators essentially promised military action against Iran if it became capable of producing nuclear weapons. There was just one little problem: they didn't bother to define what they meant by "capable."
American officials have been cautioning Israel against attacking Iran. National security advsier Tom Donilon on Sunday met with Israeli Prime Minister Benjamin Netanyahu. And other western officials have said a strike against Iran would be "destabilizing" and not "the wise thing" to do at this time, the New York Times reports.
America's negative view of China has more to do with the economy, according to the Gallup poll. Twenty-three percent of respondents view China as the United States' top enemy. It fits into the Republican narrative that America is losing its place as the world's leading nation under President Obama. Mitt Romney has campaigned against China, promising to label the country a currency manipulator on day one of his presidency unless it changes its ways.
While Americans feel anxious about China's booming economic growth, they view the country much more favorably than Iran. Americans give China a 41 percent favorable rating, according to Gallup.