Well, first off the primary reason the Normandy landings ever happened was Stalin's insistence. Dismayed at the level of casualties the Russian army was suffering, he demanded the western allies open a second front to take some the pressure off his own troops. Upon being told of the landings by Churchill he promptly telegraphed back "Your communication on the successful launching of 'Overlord' has reached me. It is a source of joy to us all and of hope for further successes." He then goes on to promise the start of a major offensive on his part between the late June and the end of July

Read the whole thing here: http://books.google.com/books?id=Cu6mqGHKFwcC&pg=PA145&lpg=PA145&dq=#v=onepage&q&f=false (scroll down to No. 201)