Halifax had, in common with Shaftesbury, and with almost all the politicians of that age, a very loose morality where the public was concerned; but in Halifax the prevailing infection was modified by a very peculiar constitution both of heart and head, by a temper singularly free from gall, and by a refining and sceptical understanding. He changed his course as often as Shaftesbury; but he did not change it to the same extent, or in the same direction. Shaftesbury was the very reverse of a trimmer. His disposition led him generally to do his utmost to exalt the side which was up, and to depress the side which was down. His transitions were from extreme to extreme. While he stayed with a party he went all lengths for it: when he quitted it he went all lengths against it. Halifax was emphatically a trimmer; a trimmer both by intellect and by constitution. The name was fixed on him by his contemporaries; and he was so far from being ashamed of it that he assumed it as a badge of honour. He passed from faction to faction. But instead of adopting and inflaming the passions of those whom he joined, he tried to diffuse among them something of the spirit of those whom he had just left. While he acted with the Opposition he was suspected of being a spy of the Court; and when he had joined the Court all the Tories were dismayed by his Republican doctrines.
He wanted neither arguments nor eloquence to exhibit what was commonly regarded as his wavering policy in the fairest light. He trimmed, he said, as the temperate zone trims between intolerable heat and intolerable cold, as a good government trims between despotism and anarchy, as a pure church trims between the errors of the Papist and those of the Anabaptist. Nor was this defence by any means without weight; for though there is abundant proof that his integrity was not of strength to withstand the temptations by which his cupidity and vanity were sometimes assailed, yet his dislike of extremes, and a forgiving and compassionate temper which seems to have been natural to him, preserved him from all participation in the worst crimes of his time. If both parties accused him of deserting them, both were compelled to admit that they had great obligations to his humanity, and that, though an uncertain friend, he was a placable enemy. He voted in favour of Lord Stafford, the victim of the Whigs; he did his utmost to save Lord Russell, the victim of the Tories; and, on the whole, we are inclined to think that his public life, though far indeed from faultless, has as few great stains as that of any politician who took an active part in affairs during the troubled and disastrous period of ten years which elapsed between the fall of Lord Danby and the Revolution.