The Radical Republican Reconstruction was a period of U.S. history from 1865 to 1877 during which the federal government sought to rebuild the South after the American Civil War. During this period, Radical Republicans in Congress passed a series of laws and amendments that sought to protect the civil rights of African Americans and to ensure that the former Confederate states were treated fairly as part of the Union. This period of Reconstruction was one of the most significant in American history, as it laid the groundwork for future civil rights movements.

The agenda of the Radical Republican Reconstruction was threefold:

1. To restore the Union and ensure that the former Confederate states were treated fairly and democratically. This was accomplished through the Reconstruction Acts, which provided for the re-admittance of the former Confederate states into the Union on the condition that they adopted a new Constitution that abolished slavery.

2. To guarantee civil rights for African Americans. This was accomplished by passing the Thirteenth, Fourteenth and Fifteenth Amendments, which abolished slavery, granted citizenship to African Americans and guaranteed all citizens the right to vote regardless of race.

3. To ensure that the former Confederate states would be economically viable by providing for the building of new infrastructure. This was accomplished through the establishment of the Freedman's Bureau, which helped former slaves to find jobs, housing, and education.

The Radical Republican Reconstruction was a period of significant political change in the United States. Its main agenda was to ensure the civil rights of African Americans and to strengthen the Union. To achieve this, the Radical Republicans pursued a number of policies, including the passage of the Civil Rights Act of 1866, the Fifteenth Amendment, the Freedmen’s Bureau, and a number of economic initiatives. Although the Radical Republican Reconstruction period came to an end in 1877, its legacy continues to be felt in the United States today.

The Radical Republican Reconstruction had a profound impact on the United States. It laid the groundwork for the civil rights movement of the 20th century, and it was a period of great progress in terms of racial equality. While the Reconstruction period was certainly not without its struggles, it was ultimately a major step forward in the fight for civil rights.