Jacques Steinberg nails down the irony of the succession decisions ABC has to make after the death of Peter Jennings. Do they move Charlie Gibson to the evening shift full time? It would be natural. But that might cost them big profits in the fight for “Good Morning America” trying to overtake “Today.” But how would that look, that now the morning shows — full of Aruba and other hardly-prestigious tabloid flotsam — are the crown jewels of network news? I know that doesn’t address the liberal-bias issue, but do you think anyone at ABC or CBS really considers that as a factor in the succession debates?