In the aftermath, the Supreme Allied Commander, General Dwight D. Eisenhower expressed his concern that a breakout was unlikely. Montgomery differed; the tenacity of the German defence was no barometer of its longevity. Field Marshal Erwin Rommel mentioned to Lieutenant-Colonel Caesar von Hofacker that the front-line in France could only be held for another three weeks. Hofacker was a member of the German resistance and linked with the Hitler assassination plot and according to Trew, Rommel's comment led to the plot timetable being decided. The serious losses sustained in maintaining a static defence during June led to fractures in the German high command. On 1 July, Panzer Group West commander Leo Geyr von Schweppenburg had been replaced by Heinrich Eberbach, following disagreements with Hitler over how the campaign should be conducted. Gerd von Rundstedt, soon followed, that evening, in a telephone conversation with "Generalfeldmarschall" Wilhelm Keitel, head of OKW, von Rundstedt said "Make peace, you fools." Taken to task over his endorsement of von Schweppenburg's recommendation for a withdrawal, he replied "If you doubt what we're doing, get up here and take over this shambles yourself". The following morning, informed that perhaps his health was "no longer up to the task", von Rundstedt resigned and was succeeded as OB West by Günther von Kluge. The costly battles in and around Caen and Saint-Lô convinced both Eberbach and von Kluge that their predecessors had been correct. The Germans had suffered heavily, leading Hitler to order Army Group B to temporarily abandon big counter-attacks and go over to the defensive until more reinforcements could arrive to bolster the front. Trew contends that the capture of northern Caen had a psychological impact on the French population, convincing them the Allies were there to stay and that the liberation of France could not be far off. By Operation Charnwood's conclusion, Allied losses since 6 June had amounted to over 30,000 men, excluding those who had been evacuated due to sickness and those suffering from battle exhaustion. Buckley believes Charnwood to have been a good idea but one that proved better in concept than in execution, influenced as it was by the mounting political pressure on 21st Army Group to produce results. Copp wrote that the broad-based assault plan across the entire front worked, preventing the Germans bringing to bear superior firepower on any one formation. Copp wrote that Charnwood should have produced a rapid breakthrough but concedes that the battle was one of the most difficult of the campaign.