But against the expectation of Napoleon III, the great rebellion in the United States collapsed, and this country became a military power which Europe was compelled to respect:  a nation that could keep in the field over a million of soldiers was not to be despised.  While the civil war was in progress the United States government was compelled to ignore the attempt to establish a French monarchy on its southern borders; but no sooner was the war ended than it refused to acknowledge any government in Mexico except that of President Juarez, which Louis Napoleon had overthrown; so that although the French emperor had bound himself with solemn treaties to maintain twenty-five thousand French troops in Mexico, he was compelled to withdraw these forces and leave Maximilian to his fate.  He advised the young Austrian to save himself by abdication, and to leave Mexico with the troops; but Maximilian felt constrained by his sense of honor to remain, and refused.  In March, 1867, this unfortunate prince was made prisoner by the republicans, and was unscrupulously shot.  His calamities and death excited the compassion of Europe; and with it was added a profound indignation for the man who had unwittingly lured him on to his ruin.  Louis Napoleon’s military prestige received a serious blow, and his reputation as a statesman likewise; and although the splendor of his government and throne was as great as ever, his fall, in the eyes of the discerning, was near at hand.

By this time Louis Napoleon had become prematurely old; he suffered from acute diseases; his constitution was undermined; he was no longer capable of carrying the burdens he had assumed; his spirits began to fail; he lost interest in the pleasures which had at first amused him; he found delight in nothing, not even in his reviews and fetes; he was completely ennuied; his failing health seemed to affect his mind; he became vacillating and irresolute; he lost his former energies.  He saw the gulf opening which was to swallow him up; he knew that his situation was desperate, and that something must be done to retrieve his fortunes.  His temporary popularity with his own people was breaking, too;—­the Mexican fiasco humiliated them.  The internal affairs of the empire were more and more interfered with and controlled by the Catholic Church, through the intrigues and influence of the empress, a bigoted Spanish Catholic,—­and this was another source of unpopularity, for France was not a priest-ridden country, and the emperor was blamed for the growing ecclesiastical power in civil affairs.  He had invoked war to interest the people, and war had saved him for a time; but the consequences of war pursued him.  As he was still an overrated man, and known to be restless and unscrupulous, Germany feared him, and quietly armed, making preparations for an attack which seemed only too probable.  His negotiation with the King of Holland for the cession of the Duchy of Luxemburg, by which acquisition he hoped to offset the disgrace which his Mexican enterprise had caused, excited the jealousy of Prussia; for by the treaties of 1815 Prussia obtained the right to garrison the fortress,—­the strongest in Europe next to Gibraltar,—­and had no idea of permitting it to fall into the hands of France.