Why did Radical Republicans try to force President Johnson out of office?

Radical Republicans were not content with taking charge of Reconstruction away from President Johnson(right), but were determined to drive the president from office. In 1867, Republicans passed the Tenure of Office Act, which declared that the president could not dismiss officials from his cabinet without the Senate's approval. When Johnson dismissed Secretary of War Edwin Stanton, the sole member of his cabinet who supported a much more sweeping effort to reconstruct the South, Radical Republicans in Congress impeached the president for violating the law. (The U.S. Constitution provides that the House of Representatives has the power to impeach presidents, judges, and other officeholders for "high crimes and misdemeanors. To impeach means to condemn. If an official is impeached in the House, he is then tried in the Senate, which has the power to remove him from office.) In a widely publicized trial in the Senate in 1868, Johnson was acquitted by only one vote. Later that year, Republican Ulysses S. Grant, who had become famous as a general during the Civil War, was elected president.