Answer: He came from humble or common beginnings.
Explanation:
The meabning of a log cabin president simply means a president that came from a humble or common beginnings. Andrew Jackson is considered to be the first log cabin president. He was born in Crawford Plantation in a cabin.
Other notable examples of log cabin presidents are James K. Polk, Franklin Pierce, Abraham Lincoln etc.
Congress thought President Lincoln was being to sincere and forgiving toward the Confederate side of the US (remember that they seceded from the Union and formed their own goverment which started the American Civil War).
The Germans sank a British ship which had American passengers. This was the first step. After this due to the unrestricted submarine warfare more US ships were sunk by German U-boats.