Why does Petraeus hate Bush’s legacy troops in the field?

Gen. David Petraeus told the Senate today he is against more U.S. troop drawdowns in Iraq:

Petraeus told a Senate hearing that he recommends a 45-day "period of consolidation and evaluation" once the extra combat forces that President Bush ordered to Iraq last year have completed their pullout in July. He did not commit to a timetable for resuming troop reductions after the 45-day pause. …

Petraeus said his approach takes account of the fact that security gains achieved over the past year are fragile and reversible, and he said it is intended to “form a foundation for the gradual establishment of sustainable security in Iraq.” But he did not say when he thought that goal would be reached.

“Withdrawing too many forces too quickly could jeopardize the progress of the past year,” Petraeus said.

What this means, claims of Bush and Defense Secretary Bob Gates aside, is that U.S. troops will stay on a 15-12 rotation rather than a 12-12 one.

I’ll bet five bucks that nobody calls him out on that in the hearing, though.