Which brings to mind your beloved Tyrant...
Tyr´ant Pronunciation: tÄ«´rant n. 1. An absolute ruler; a sovereign unrestrained by law or constitution; a usurper of sovereignty. 2. Specifically, a monarch, or other ruler or master, who uses power to oppress his subjects; a person who exercises unlawful authority, or lawful authority in an unlawful manner; one who by taxation, injustice, or cruel punishment, or the demand of unreasonable services, imposes burdens and hardships on those under his control, which law and humanity do not authorize, or which the purposes of government do not require; a cruel master; an oppressor.
Sounds like Lincoln to me..........
Sounds more like Davis. Lincoln ran and won two contested elections, Davis didn't. Lincoln was constrained by a Supreme Court, Davis wasn't. Lincoln had a political opposition in Congress, Davis didn't. Davis ignored his constitution and trampled on state's rights and civil rights in ways Lincoln never imagined. If tyrant is to be correctly applied to one or the other, then I suggest Davis more closely fits the term.
He was a dictator, hiding behind a rump cabinet, with a congress out of town and a judiciary being threatened with arrest.