I am still reading Forge of Empires, and may have more comments down the road. For now, I'll quote a passage from p. 169 that gives a good sense of the book's style and substance:
Lincoln read the newspapers. In the autumn of 1862 the fate of liberty hung in the balance in three great nations. It hung in the balance in Russia, where an absolute ruler sought to promote liberal reform but was unable to overcome the inertia of despotism. It hung in the balance in Germany, where a minister of the Prussian crown applied his dark genius to the destruction of the last feeble props of the Rechtsstaat (a state under the rule of law). And it hung in the balance in America, where Lincoln himself struggled to preserve the free institutions of his country from the evils of domestic rebellion and the machinations of Old World powers, as well as from the temptations to meet those difficulties in a manner fatal to the very conception of liberty he sought to vindicate.