[In 2008 Barack Obama] was running to be America’s first black president, which assumed that skin color and the ethnicity of one’s father outdistanced every cultural factor including who actually raised you. In fact, here is Wikipedia’s summary of Obama’s experience with his black father:
On August 4, 1961, at the age of 18, [Ann] Dunham gave birth to her first child, Barack Obama II. She took classes at the University of Washington from September 1961 to June 1962, and lived as a single mother in the Capitol Hill neighborhood of Seattle with her son while her husband continued his studies in Hawaii. When Obama Sr. graduated from the University of Hawaii in June 1962, he was offered a scholarship to study in New York City, but declined it, preferring to attend the more prestigious Harvard University. He left for Cambridge, Massachusetts, where he would begin graduate study at Harvard in the fall of 1962. Dunham returned to Honolulu and resumed her undergraduate education at the University of Hawaii with the spring semester in January 1963. During this time, her parents helped her raise the young Obama. Dunham filed for divorce in January 1964, which Obama Sr. did not contest.
In other words, in less than three years, young Obama’s time with his black father was over. He was thereafter raised by a white mother and white grandparents. But because our definition of ethnicity – whether we be black, white, conservative, or liberal – favors simplistic and visible biological evidence over actual cultural history, Obama had no trouble running as a black as long as he kept his actual upbringing in the background. And the fact that categorizing people by the color of their skin is a deeply racist concept got no attention at all.