Lord Voldemort had just discovered the spell that enabled him to make his name taboo.
Of course, it was already taboo in a way, as normally, people wouldn't use it out of fear, but that was just what made the actual taboo attractive.
If he used this spell, he could listen in to any conversation his name was used in. As the main person to use his name was also the main person to plot against him, this would be highly useful. Any plot against him that included Dumbledore would reach his ears immediately.
Ten weeks later, Lorad Voldemort managed to set up an ambush and kill Albus Dumbledore, after he spoke of visiting his brother Aberforth for tea right after discussing plans for the Order of the Flaming Chicken. After his death, resistance slowly broke down to a minimum.