Answer:
Congress could not tax, regulate trade, or conduct foreign policy without the voluntary agreement of the states. They also could not raise a military force. These were all weaknesses of the Articles.
The sinking of the Lusitania caused significant problems between the US and Germany. This British ocean liner (aka ship), that had American citizens on it, was sunk by a German submarine in May of 1915. This was in the midst of World War I, which the United States was trying to stay out of.
However, after this incident, it became increasingly difficult to do this since over a hundred American citizens were killed by the attack of the Lusitania by the German navy. These American citizens were not part of the war effort by any means and were considered innocent civilians.
This caused a serious of tense exchanges between the US and German government. The US blamed Germany for their abuse of power and use of submarine warfare. The German government argued that they warned America that any ship that entered a specific territory would be met with force.
Ultimately another German action, the sending of the Zimmerman Telegram, lead America into World War I.
They spent it on farming or buying food building better houses