It seems that this source seeks to lighten the historical judgment that has been rendered on the United States' use of the bomb in World War II.  The source points out to the rationalizations and defenses offered by its proponents at the time of its dropping.  The idea of saving military lives as well as ensuring that its targets were strictly in the line of war are part of the primary motivation of the document.  The bias is in favor of the United States, in trying to justify the use of the device.  The reality is that the source (or the excerpt featured) does not discuss some of the harsh truths that came out of dropping of the bomb.  While the target might have been military in nature, the causalities were predominantly civilian.  Additionally, there is much which suggests that had a demonstration of the device been given to Japanese diplomats, there could have been a greater chance to bringing them to the negotiation table without detonating the device on so many civilians.

If there is an ideological perspective in this source, you can say it is one of American nationalism.  I do not really think there is much of a bias here, but perhaps I share the same bias and do not see it.

You can argue that this is American nationalism because it is attempting to justify the dropping of the atomic bombs on Japan.  However, I do not think that it really is nationalism.  I think that nationalism occurs when you blindly take your country's side.  I think that this passage actually gives good arguments for the American position rather than agreeing blindly with that position.