In the latest proof that the fall presidential election will be a nail-biter, a new and authoritative analysis of the factors weighing on President Obama finds that he will edge out Mitt Romney, becoming the first-ever two-term African-American in the Oval Office.

Going far beyond the normal review of job approval which typically is the best election predictor, Larry Sabato’s University of Virginia Center for Politics team also factored in the economy and the public’s desire for change. The bottom line: Obama will win 51 percent of the vote.