In the end, Dumbledore still did not draw his wand and give Umbridge a good hard blast.
Professor McGonagall left too. After Umbridge had gone, she stomped heavily across the floor, leaving one remark behind-
"Sometimes I really don't understand you, Albus."
To be honest, Su Er also felt that Dumbledore could have drawn his wand and blasted Umbridge just then. His behavior had been entirely at odds with the spirit a powerful man ought to have, letting someone much weaker walk all over him...
"Having power doesn't always mean you can do whatever you please, does it?"
As though he could see through Su Er's thoughts, Dumbledore gazed toward the doorway after Professor McGonagall left and spoke softly.
"Wizards' power has grown in every field, except for their power of self-restraint."
Only because Dumbledore kept yielding had Umbridge and Fudge naively believed they could control Hogwarts, allowing the desires in their minds to swell until they ultimately led themselves to ruin.
As expected of that sly old bas-no, that master strategist...
Su Er understood.
Dumbledore was not merely explaining. These words were also telling Su Er to exercise self-restraint, not to use the power within him at an inappropriate time. That would only lead to destruction.
Just as that blind monk had once said-"Master yourself, master your enemy."
The Headmaster's Office fell quiet for a while before Dumbledore turned around, took out his wand, and tapped himself lightly. His purple, star-studded robes swiftly changed into plain dark blue wizard robes without a pattern.
"If you have nothing else to do, would you accompany me to St. Mungo's? I really am rather worried about Arthur."
At that very moment, Su Er had been about to tell Dumbledore what he had seen-the change in Harry at the instant the Portkey activated.