No.
The Japanese were not "suing for peace" prior to the bombings of Hiroshima and Nagasaki.
Does Denson's article portray the situation in May-Jul 1945 accurately?
No, Dulles' contacts had limited support and did not represent the Japanese government...
In early 1945 Japanese navy circles in Berlin tried to begin peace
negotiations with the United States. Using their contacts with the
arms trader Friedrich Wilhelm Hack, they sent Commander Fujimura
Yoshikazu to Switzerland, where he opened talks with Allen W. Dulles
of the U.S. Office of Strategic Services. Though the Japanese navy and
Foreign Ministry showed some interest, the peace attempts finally
failed since neither side took the initiative to an official level.
Fujimura confused his government by claiming that the Americans had
made the first step, while the U.S. side waited for proof that the
administration in Tokyo was backing the navy officer's initiative. -
(Krebs 2005, see pp. 1108-1112)
Furthermore...
The most often repeated condemnation of American diplomacy in the
summer of 1945 is that policy makers understood that a promise to
retain the Imperial institution was essential to end the war, and that
had the United States communicated such a promise, the Suzuki cabinet
would likely have promptly surrendered. The answer to this assertion
is enshrined in black and white in the July 22 edition of the
Magic Diplomatic Summary. There, American policy makers could read for
themselves that Ambassador Sato had advised Foreign Minister Togo
that the best terms Japan could hope to secure were unconditional
surrender, modified only to the extent that the Imperial institution
could be retained. Presented by his own ambassador with this offer,
Togo expressly rejected it. Given this, there is no rational
prospect that such an offer would have won support from any of the
other live members of the Supreme Council for the Direction of the
War. - (Frank 1999, p. 239)
I would like at least a sketch of the elements within the Japanese government who were in a position to control the surrender and an understanding of those elements' position on surrender.
As historian Robert Butow pointed out in 1954, the fate of Japan
rested in the hands of only eight men. These were the emperor, his
principal advisor Marquis Koichi Kido, and an inner cabinet of the
government of Admiral Kantaro Suzuki called the "Big Six": Prime
Minister Suzuki, Foreign Minister Shigenori Togo, Army Minister
General Korechika Anami, Navy Minister Admiral Mitsumasa Yonai, Chief
of the Army General Staff General Yoshijiro Umezu, and Chief of the
Navy General Staff Admiral Soemu Toyoda.
There is no record whatsoever that any of these eight men proposed a
set of terms or circumstances in which Japan would capitulate prior to
Hiroshima. More significantly, none of these men even after the war
claimed that there was any set of terms of circumstances that would
have prompted Japan to surrender prior to Hiroshima. The evidence
available shows that in June, a memorandum from Kido to the emperor
proposed that the emperor intervene not to surrender, but to initiate
mediation by a third party. The mediation would look to settle the war
on terms that echoed the Treaty of Versailles: Japan might have to
give up its overseas conquests and experience disarmament for a time,
but the old order in Japan would remain in charge. Certainly there
would be no occupation and no internal reform. - (Frank 2009)
Sources
See also