According to Gallup, President Obama is tied with George W. Bush for most unpopular re-elected president since Gallup began measuring presidential job-approval in 1945.
In fact, Gallup found that apart from Bush, "every president...has had a higher job-approval rating in the January following his reelection than Obama has."
Obama's approval rating is at 52.
Think about it this way--following reelection, President Reagan's approval numbers beat Obama's by 11 points, President Eisenhower's beat Obama's by 21, and a much-derided Republican President named Richard Nixon beat Obama's numbers by 7.
Hardly representative of a mandate and certainly a long way from supporting the misconception that Obama is lauded by the public while Republicans are despised.