Answer:
He supported the quick restoration of the seceded states to the Union without protection for the former slaves
Step-by-step explanation:
Andrew Johnson's provocative action leading the radical republicans in congress to seek his ouster is that "he supported the quick restoration of the seceded states to the Union without protection for the former slaves."
Before the American Civil war in 1861, it was only the majority of the North and Republicans that supported the abolition of slavery. Hence, following the loss of Confederates/Seceded states after the War in 1865, and the subsequent assassination of President Abraham Lincoln, Andrew Johnson becoming the new President of the United States " supported the quick restoration of the seceded states to the Union without protection for the former slaves." This situation led to Congress inclined along Republicans to seek his impeachment