I was not a supporter of him politically, but I knew him more intimately than I did any other of the volunteer generals."[66]

Return to New Hampshire
By the 1850s, Pierce had become a de facto leader of the New Hampshire Democratic Party.[67]
Returning to Concord, Pierce resumed his law practice; in one notable case he defended the religious liberty of the Shakers, the insular sect threatened with legal action over accusations of abuse. His role as a party leader, however, continued to take up most of his attention. He continued to wrangle with Senator Hale, who was anti-slavery and had opposed the war, stances that Pierce regarded as needless agitation.[67]
The large Mexican Cession of land divided the United States politically, with many in the North insisting that slavery not be allowed there (and offering the Wilmot Proviso to ensure it), while others wanted slavery barred north of the Missouri Compromise line of 36°30′ N. Both proposals were anathema to many Southerners, and the controversy split the Democrats. 