Which event helped convince the United States to enter world war 1 on the side of the allies
1. Assassination of Archduke Franz Ferdinand
2. Overthrow of the Russian tsar
3. Election of Woodrow Wilson
4. Sinking of Lusitania
That would have to be 4. Sinking of Lusitania (This very boat was used as part of the address to Congress the president made to ask them to go to war.)
