As a result, only 49 percent of Hispanics are eligible to vote, compared with 74 percent of non-Hispanics. Hispanics make up just 11 percent of the voting-eligible population.

Eligible Hispanics are also less likely to vote than other Americans. A big part of the reason is demographic: Hispanics are younger than other Americans, and voters of all racial and ethnic backgrounds become significantly more likely to vote as they age. In 2012, the turnout rate for potential Hispanic voters was 48 percent, compared with 66.2 percent among blacks and 64.1 percent among whites. The lower Hispanic turnout rate is not as significant a factor as eligibility and geography, but it does further reduce the Hispanic share of the electorate, especially in midterm elections.

The power of Hispanic voters is further diluted by geography. Hispanics are disproportionately concentrated in large states, like California, Florida and Texas. Incredibly, Hispanics represent an above average share of the population in only nine of the 50 states. There are very few Hispanic voters in most small states, like Wyoming or the Dakotas, and small states are overrepresented in the political process, thanks to the structure of the Senate. Effectively, the Hispanic share of the eligible Senate electorate is just 7.5 percent.