National Journal's Ron Brownstein saysRomney's camp is hoping to capture 61% of white voters this year. That will give them a majority so long as whites make up 74% of the electorate (the same as in 2008) and Barack Obama does not improve on his 80% performance with minority voters.
That 61% goal is a lofty one. Only Dwight Eisenhower hit that mark in 1952. Ronald Reagan and George H.W. Bush got close, grabbing between 56 and 61%.
These calculations underscore the depth of racial polarization shadowing this election and the achingly slim margin of error facing each candidate. If Obama nudges past 80 percent among minorities (which seems very possible) or the minority vote share rises (also possible, though less probable), the president could gain reelection while winning only about 38 percent of white votes. Conversely, if the white proportion of the vote increases just a single percentage point (to 75 percent), and Romney records any gains among minorities, he could shave his winning number to a more manageable 59 percent of whites.

