RF: Did the international Laws of War apply to the war between USSR and the Third Reich?
If so, why were they not respected?

Sources:
http://www.yale.edu/lawweb/avalon/lawofwar/lawwar.htm
http://en.wikipedia.org/wiki/Geneva_Convention
http://www.eda.admin.ch/eda/f/home/foreign/intagr/train/iprotection.html
http://www.icrc.org/IHL.nsf/
http://www1.umn.edu/humanrts/index.html

First Geneva Convention
Convention for the Amelioration of the Condition of the Wounded in Armies in the Field. Geneva, 22 August 1864
Prussia Signature 22.08.1864, Ratified Accession 04.01.1865
Russia Ratified Accession 22.05.1867

Convention (II) with Respect to the Laws and Customs of War on Land and its annex: Regulations concerning the Laws and Customs of War on Land. The Hague, 29 July 1899.
Germany Signature 29.07.1899, Ratif. Accession 04.09.1900
Russia Signature 29.07.1899, Ratif. Accession 04.09.1900

Convention for the Amelioration of the Condition of the Wounded and Sick in Armies in the Field. Geneva, 6 July 1906.
Germany Signature 06.07.1906, Ratif. Accession 27.05.1907
Russia Signature 06.07.1906, Ratif. Accession 09.02.1907

Convention (III) relative to the Opening of Hostilities. The Hague, 18 October 1907.
Germany Signature 18.10.1907, Ratif. Accession 27.11.1909Russia Signature 18.10.1907, Ratif. Accession 27.11.1909
http://www.yale.edu/lawweb/avalon/lawofwar/hague03.htm

Convention (IV) respecting the Laws and Customs of War on Land and its annex: Regulations concerning the Laws and Customs of War on Land. The Hague, 18 October 1907.
Germany Signature 18.10.1907, Ratif. Accession 27.11.1909
("Under reservation of Article 44 of the annexed Regulations.")
Article 44
"Any compulsion of the population of occupied territory to take part in military operations against its own country is prohibited."

Russia Signature 18.10.1907, Ratif. Accession 27.11.1909
("The delegation of Russia has the honour to declare that having accepted the new Article 22a [which became Article 23, paragraph 2], proposed by the delegation of Germany, in the place of Article 44 of the existing Regulations of 1899, it makes reservations on the subject of the new wording of the said Article 44a")
Art. 44
A belligerent is forbidden to force the inhabitants of territory occupied by it to furnish information about the army of the other belligerent, or about its means of defense.

Second Geneva Convention
Convention for the Amelioration of the Condition of the Wounded and Sick in Armies in the Field. Geneva, 27 July 1929. (Convention de Geneve pour l'amelioration du sort des blesses et des malades dans les armees en campagne faite a Geneve le 27 juillet 1929)

Germany Signature 27.07.1929, Ratif. Accession 21.02.1934, Effective 21.08.1934
USSR Ratif. Accession 26.09.1931, Effective 26.03.1932
(“The act of accession was accompanied by the following declaration by which Article 9 of the Convention is understood by the Government of the Union in the sense that all military personnel on active service but affected to medical formations and establishments will be subject to the treatment provided for in the above-mentioned Article.”)

Art. 9.
The personnel engaged exclusively in the collection, transport and treatment of the wounded and sick, and in the administration of medical formations and establishments, and chaplains attached to armies, shall be respected and protected under all circumstances. If they fall into the hands of the enemy they shall not be treated as prisoners of war.
Soldiers specially trained to be employed, in case of necessity, as auxiliary nurses or stretcher-bearers for the collection, transport and treatment of the wounded and sick, and furnished with a proof of identity, shall enjoy the same treatment as the permanent medical personnel if they are taken prisoners while carrying out these functions.

Most important is the Third Geneva Convention.

CONVENTION OF JULY 27, 1929, RELATIVE TO THE TREATMENT OF PRISONERS OF WAR. (Convention de Geneve relative au traitement des prisonniers de guerre
faite a Geneve le 27 juillet 1929)

Germany Signature 27.07.1929, Ratif. Accession 21.02.1934, Effective 21.08.1934
USSR - No Signature

The introduction to the document lists “The President of the German Reich” as a Participant to the convention,
“recognizing that, in the extreme case of a war, it will be the duty of every Power to diminish, so far as possible the unavoidable rigors thereof an to mitigate the fate of prisoners of war;
desirous of developing the principles which inspired the international conventions of The Hague, in particular the Convention relative to the laws and customs of war and the Regulations annexed thereto;”

Here is a section that makes it clear that if the Third Reich actually respected the convention in regards to any POW’s, then the excuse that Soviet POW’s were not treated accordingly because USSR was not party to the Convention simply cannot apply!

TITLE VIII. EXECUTION OF THE CONVENTION.
SECTION I. GENERAL PROVISIONS.
ARTICLE 82.
The provisions of the present Convention must be respected by the High Contracting Parties under all circumstances.
In case, in time of war, one of the belligerents is not a party to the Convention, its provisions shall nevertheless remain in force as between the belligerents who are parties thereto.

A more general approach would consider all other international conventions that Germany had been party to and compare to them to the actual actions of the Third Reich.