Worries about political extremism or threats to democracy have emerged as a top concern for U.S. voters and an issue where President Joe Biden has a slight advantage over Donald Trump ahead of the November election‚ a new Reuters/Ipsos poll showed. Some 21% of respondents in the three-day poll‚ which closed on Sunday‚ said "political extremism or threats to democracy" was the biggest problem facing the U.S.‚ a share that was marginally higher than those who picked the economy - 19% - and...