The first lady is making a new push to increase voter turnout.
Sen. Jeanne Shaheen (D-N.H.) holds a consistent lead over her challenger.
In a hypothetical rematch, Romney would top Obama 53 percent to 44 percent.
Republicans are hopeful about late-breaking opportunities in a pair of swing states.
Sen. Lamar Alexander faces what could be his toughest GOP race yet.
Laura Barron-Lopez 07/26/14 04:16 PM EDT
Obama was joined by Tony Kornheiser and Michael Wilbon of ESPN's "Pardon the Interruption."
Some lawmakers in Congress are too focused on ideological ideals, she said.
Laura Barron-Lopez 07/26/14 01:00 PM EDT
GOP Senate candidate Ed Gillespie said he thinks there's evidence to support climate change.
Laura Barron-Lopez 07/26/14 12:01 PM EDT
"Because of Obama and Warner's job-killing policies more businesses are closing," he said.
Timothy Cama 07/25/14 05:48 PM EDT
The League of Conservation Voters said Schatz has a strong record of fighting pollution.