President Donald Trump campaigned Monday in Mississippi, as he continued a closing midterm rally blitz that has highlighted Republicans' challenges ahead of an election that could drastically shift power in Washington and statehouses across the country."I'm here because Cindy's doing great, but I just got to make sure. I can't take a chance," Trump told the crowd, his voice audibly hoarse, as he worked to boost Republican Sen. Cindy Hyde-Smith, who is facing a surprisingly stiff challenge from Democrat Scott Colom.Colom was spotted at the rally site, too, creating the rare spectacle of Trump's staunchest supporters interacting directly with a...