Carson rose to prominence in the tea party movement after repudiating the president's health care law in front of Obama during the 2013 National Prayer Breakfast. Carole Bell, a professor of communication studies at Northeastern University, estimates that Carson could attract as much as 25 percent of the African-American vote if he's the GOP candidate. Carson is better known by African-American voters than were other black Republicans who ran for president, such as businessman Herman Cain, who achieved passing prominence in the 2012 race, and former ambassador Alan Keyes before him. Carson led a team that successfully separated conjoined twins, which led to movie appearances, best-selling books, a television biography and a motivational speaking career that crossed racial lines. "Black people were proud that Carson had become a famous surgeon and had accomplished what no one else ever had in separating the twins," said Fredrick Harris, director of the Institute for Research in African-American Studies at Columbia University. Carson has said he would not support a Muslim for president, a position his campaign says helped him raise money and attract conservative support. Carson may draw support from conservative African-Americans and those already in the GOP, but it's unlikely that he would make major inroads in the Democratic Party's dominance among blacks in a general election, said D'Andra Orey, a political science professor at Jackson State University in Jackson, Mississippi. Given the GOP's fraught history with African-Americans, it could be "nearly impossible for blacks to support a Republican who espouses what they deem to be racially conservative rhetoric," Orey said.