In this pledge Great Britain and Spain were sincere.  Napoleon III was not—­was indeed pursuing a policy not at first understood even by his Ministers[546].  A joint expedition under the leadership of the Spanish General Prim was despatched, and once in Mexico took possession of customs houses and began to collect duties.  It soon became evident to the British and Spanish agents on the spot that France had far other objects than the mere satisfaction of debts.  The result was a clash of interests, followed by separate agreements with Mexico and the withdrawal of forces by Great Britain and Spain.  This difference of view on Mexican policy had become clear to Cowley, British Ambassador at Paris, by January, 1862, and from that month until the end of March his private letters to Russell referring to American affairs in general are almost wholly concerned with French designs on Mexico.  Cowley learned that earlier rumours of Napoleon’s purpose to place the Archduke Maximilian of Austria upon the Throne of Mexico, far from being unfounded, were but faint indications of a great French “colonial Empire” scheme, and he thought that there was “some ill-will to the United States at the bottom of all this[547]....”  He feared that the Mexican question would “give us a deal of trouble yet[548],” and by March was writing of the “monstrous claims on the Mexican Govt.” made by France[549].

These reactions of Cowley were fully shared by Russell, and he hastened, in March, to withdraw British forces in Mexico, as also did Spain.  Great Britain believed that she had been tricked into a false position in Mexico, hastened to escape from it, but in view of the close relation of joint policy with France toward the Civil War in America, undertook no direct opposition though prophesying an evil result.  This situation required France to refrain, for a time, from criticism of British policy and action toward the North—­to pursue, in brief, a “follow on” policy, rather than one based on its own initiative.  On the British side the French Mexican policy created a suspicion of Napoleon’s hidden purposes and objects in the Civil War and made the British Government slow to accept French suggestions.  The result was that in relation to that war Great Britain set the pace and France had to keep step—­a very advantageous situation for the North, as the event was to prove.  On the purely Mexican question Lyons early took opportunity to assure Seward that Great Britain was “entirely averse to any interference in the internal affairs of Mexico, and that nothing could be further from their wishes than to impose upon the Mexican Nation any Government not of its own choice[550].”