HISTORY - Hiroshima: Was the atomic bomb necessary?

As Barack Obama becomes the first sitting US president to visit Hiroshima, should the US apologize for dropping the atomic bombs on Japan? 

The mainstream view of the bombing of Hiroshima and Nagasaki in 1945 is that it was needed in order to force Japan to surrender and bring an end to the war, but a look at history shows that some prominent military commanders and politicians thought otherwise. 

In this week's Reality Check, Mehdi Hasan asks if use of the bombs was justified; and as President Obama visits Hiroshima, should the US apologize to the victims of the bombings?