Set their own working hours
1)Germans sinking US merchant ships taking supplies to England
2)Japan's unreasonable demands on the United States (re- instating oil sales and dropping support of the Philipeenes and China)
3)German submarines beginning to shoot at US war ships
4)England and France are typically our allies so we were going to enter the war eventually anyway
5)Pearl Harbor was obviously why we entered the war.
"The following month, Germany sunk four more U.S. merchant ships. ... On April 6, 1917, the United States entered World War I. Get a firsthand look at how a new breed of weapons like WMDs, submarines, armored tanks and air attacks changed modern warfare forever in WWI: The First Modern War"
To "scour" means to clear an area or region of enemies or outlaws (i.e. "scour the area for our enemies and make sure they are eliminated). To "search" is to examine an area or region with the intention of locating something or someone. "Scouring" involves locating and eliminating an enemy; to search is to simply locate someone or something.