Why might Johnson have chosen to be lenient toward many Confederates?

Andrew Johnson (1808-1875), the 17th U. S. president, assumed office after the assassination of Abraham Lincoln (1809-1865). Johnson, who served from 1865 to 1869, was the first American president to be impeached. A tailor before he entered politics, Johnson grew up poor and lacked a formal education. He served in the Tennessee legislature and U. S. Congress, and was governor of Tennessee.