How do voter registration requirements affect voter turnout?

What will be an ideal response?

An ideal response will:
1, Explain how the United States is different from other democracies in that the burden of voter registration falls on the citizen.
2, Explain that because registration is something voters do infrequently, they are less likely to know how to do it and more likely to fail to understand the process. This can lead to voter frustration and exclusion.