I.Go Tell the Californians...(1853-1856)
The (16)Z1 divergence point in 1832 has its first effects on the European continent, where a few subtle changes in Karl Marx and Fredrick Engels' biographies start a chain of differences that will be more fully discussed later in a companion piece to this one (titled 'Tonic of the Masses'). Apart from very subtle causal chains and QBE phenomenona, the divergent European, African, and East Asian history does not begin to substantially directly influence events in the Americas until the spread of the Century War to those shores in '04, so the two hemispheres are most clearly discussed separately up to that point.
The first macrodivergence in the Western Hemisphere occurs in May of 1853, in Mexico City where Santa Anna's government, even less popular and stable than the (17+) line's, is shaken by a major riot and fire in Mexico City. The military grudgingly restores order quickly, but not before the blaze claims a death toll nearing 100 and including much of the staff of the America embassy, James Gadsden included.
While the Pierce government accepts Mexico's blamelessness in the tragedy, many citizens do not, and as a direct result of this, William Walker finds many more supporters and joiners for his Baja California/Sonora fillibuster, and with those added resources finds more success. In some ways he finds himself a victim of his own success: with enough troops to credibly hold the cities of Lower California, his officers and supporters expect him to do that rather than make a stronger push into Sonora. Apart from minor skirmishes, he fights and wins two major battle with the Mexican Army, first disrupting a landing of troops near La Paz, and second and more celebrated, defeating a nominally superior Mexican force near Puerto Azufre. This second battle attracts comparisons in the contemporary media to Thermophlae like dung attracts flies, although the comparing parties are always quick to point out the happier outcome for the 'New Spartans' defending the Sulfurous Gates.
Santa Anna's government sues for peaces and, bringing the US into the negotiations, achieves in a tripartate agreement that includes a fast track to statehood for Lower California and a direct sale land sale to the US that includes the territory under discussion in the Gadsden purchase as well as the additional land required to make Arizona's southern border a straight horizontal to the Gulf of California. Pierce, privately displeased with the highly popular Walker, delays action on the statehood petition with the help of the Northern faction in Congress, and attempts to install a territorial governor, but Walker refuses to resign his title as President of the Republic of Lower California at any point prior to statehood, a position that is a colorable reading of the Treaty. By 1856, immigration has swelled the population of the peninsula to a point where further delay is impossible, and Lower California and Minnesota become the 32nd and 33rd states of the union.