Final answer:
Five constitutional amendments - the 15th, 19th, 23rd, 24th, and 26th - have expanded the U.S. electorate by removing barriers based on race, gender, residency, economic status, and age.
Step-by-step explanation:
The amendments to the U.S. Constitution that have increased the size of the electorate and the groups they cover are:
- 15th Amendment - Removed barriers based on race and color; allowed African American men to vote.
- 19th Amendment - Removed barriers based on gender; granted women the right to vote.
- 23rd Amendment - Granted residents of Washington D.C. the right to vote for the president.
- 24th Amendment - Eliminated poll taxes, removing economic barriers to voting.
- 26th Amendment - Lowered the voting age from 21 to 18, extending suffrage to younger citizens.
In addition to these formal amendments, various laws passed by Congress have also expanded voting rights and addressed issues of voter suppression.