America's turnout in recent memory has been that of trailing behind other developed countries in voter turnout.
There are some commentators that have identified voter apathy as a key cause of America's low turnout.
Voter apathy is when voters do not feel like their vote matters or that there is anyone worth voting for in the current election.
This has meant that by the time that the general election comes around, people who support candidates in the primary election may be tuned out due to the loss of their candidate and the lack of their preferred candidate in the general election. Voters are apathetic, in short.