He was also the first President to be impeached in 1868, but was later acquitted in the Senate. When a president is removed by Congress, the House of Representatives must vote to impeach him, and then the Senate to convict, by a 2/3-majority. Although the Republicans had that many senators, the conviction failed by one vote. Several Republicans thought it was not their job to replace the president, and that the charges against Johnson were made up. So Johnson could keep his job for the last year. There would be another 130 years before another president was impeached, Bill Clinton in 1998. Johnson was the only U.S. president never to have gone to school, and was taught to read by himself and by his wife, Eliza McCardle Johnson. He also taught himself law and politics by reading himself. The U.S. purchased Alaska from Russia for $7.2 million (the price was 2 cents per acre) while he was president, but it was Secretary of State William Seward who arranged the buy. It is now considered a very wise move and the natural resources in Alaska today are worth many billions.