The common utterance of loyal subjects of a monarchy applies as readily to General Motors’ changing of the guard as it did when being King of the Britons meant something. Out is GM lifer Rick Wagoner, in is GM lifer Fritz Henderson. Mr. Henderson is charged with pushing another restructuring boulder up the hill and keeping it from rolling off.

After the government autos task force turned its nose up at the tepid plan GM put forth, the former industrial titan now has 60 days to get it right or get into bankruptcy. Henderson has pledged to restructure the company one way or the other.

The 50-year-old Harvard MBA is faced with a task that mandates a smaller company—there is no other option. Turning a money-losing behemoth into one sized for profitability given its global market share will require intestinal fortitude no other GM executive has ever demonstrated.

Dismantling the institutional structure means Mr. Henderson will have to sacrifice sacred cows, scorch the earth of several divisional fiefdoms and disown several pretenders to the throne. Friendships and business relationships in and out of GM will be destroyed for the greater good. The Renaissance Center will become a bloodless version of the Tower of London.

Despite Mr. Henderson’s enthusiasm for his task, it is an unenviable position, for he is soon to be the loneliest man in the kingdom.