In the history of the United States of America, it has been often suggested (and often rejected) that some manner of test be submitted to voters prior to allowing them to register to vote. These suggestions have often been refused on the grounds of showing clear favoritism towards certain nationalities and supposedly excluding others.
In order to ensure a more informed populous without discriminating upon outlier groups, a broad-spectrum test should be designed to require basic knowledge of the government and the functions of its branches prior to entering a voting booth. Naturalized citizens undergo far more rigor than such a test would require. Suggested areas of knowledge involve knowing generally what branch does what, ie, the budget is a Congressional power, not Presidential.