Define "suffrage" as related to the Illinois Constitution.

Suffrage refers specifically to the right to vote in elections. In the context of the Illinois Constitution, it is a fundamental concept that ensures citizens have the ability to participate in the democratic process by casting their votes for elected representatives and on various measures. This right is crucial for maintaining a representative government and empowering individuals to have a say in the governance of their state and country.

The other options provided relate to different aspects of civic life. For instance, protection from unfair treatment refers to civil rights and liberties, while the obligation to pay taxes is about civic responsibilities that fund government operations. The right to run for public office pertains to the eligibility criteria for individuals who wish to seek election, rather than the act of voting itself. Hence, suffrage is distinctly associated with the act of voting, making it the correct choice in this context.