As I explained in another comments below, many top US military commanders believed that Japan was on the verge of surrender, with or without the atomic bombs.

General Dwight Eisenhower:

I voiced to him my grave misgivings, first on the basis of my belief that Japan was already defeated and that dropping the bomb was completely unnecessary, and secondly because I thought that our country should avoid shocking world opinion by the use of a weapon whose employment was, I thought, no longer mandatory as a measure to save American lives. It was my belief that Japan was, at that very moment, seeking some way to surrender with a minimum loss of 'face'.

Admiral William Leahy, Chief of Staff to the Commander in Chief:

It is my opinion that the use of this barbarous weapon at Hiroshima and Nagasaki was of no material assistance in our war against Japan. The Japanese were already defeated and ready to surrender because of the effective sea blockade and the successful bombing with conventional weapon.

Admiral Chester Nimitz, Commander in Chief, United States Pacific Fleet:

The atomic bomb played no decisive part, from a purely military standpoint, in the defeat of Japan.

General Henry Arnold, Commanding General of the US Army Air Force:

The Japanese position was hopeless even before the first atomic bomb fell, because the Japanese had lost control of their own air ... it always appeared to us that, atomic bomb or no atomic bomb, the Japanese were already on the verge of collapse.

I don't understand why you object to the original argument. Is OP wrong when he indicates that, in lieu of the bombs, the USA would have invaded and thus spent even more lives?

I objected because it is incorrect. It is a false dichotomy to say that it it was either the atomic bombs or an invasion. Most historian agree that Japan would have surrendered without either.

Again, I am not interesting in litigating the correctness of the atomic bombings. All I wanted to do is point out that (1) it is not true that an invasion was necessary without the bombs, and that (2) by ending the war early, many lives were saved from starvation because the Japanese harvest had failed and its transport network crippled.

As early as 1946 the United States Strategic Bombing Survey reported that:

Based on a detailed investigation of all the facts and supported by the testimony of the surviving Japanese leaders involved, it is the Survey's opinion that certainly prior to 31 December 1945 and in all probability prior to 1 November 1945, Japan would have surrendered even if the atomic bombs had not been dropped, even if Russia had not entered the war, and even if no invasion had been planned or contemplated.