Pastor in combat?

Some classify the Mexican War (mid-1840's) as "unjust."

It was opposed by most of the members of the Whig party as a thinly disguised attempt by the southern Democrats to grab land that would probably eventually become slave territories, not to mention as a way to upset the balance of "free" / "slave" states in the US Senate.

After the war, the controversial Compromise of 1850, and the presidential victory of Franklin Pierce in 1852, many of the disenchanted Whigs (along with a smattering of other "third parties") proceeded to unite to form a new political party--the Republican Party.