Because it was a US territory-hence a direct attack on the US. How else could we respond.
The attack on Pearl Harbor is how the United States became involved in WW2
WW2
The attack on Pearl Harbor is what brough the United States into WW2
Japan's attack on Pearl Harbor convinced the United States to come out of their isolation policy and join WW2.
It created WW2.
WW2
ww2........................ -.-
WW2.
Pearl Harbor
Japan's attack on Pearl Harbor convinced the United States to come out of their isolation policy and join WW2.
The us joined ww2
The Japanese attack on Pearl Harbor.