Historically, Willie P. Mangum was President Pro Tem of the Senate between 1841 and 1845. The president of the time, John Tyler, had been vice president until the death of President Harrison. At that time there was no provision for a new vice president to be appointed if a president or vice president died. Until the succession laws were revised in 1886, the president pro tem of the senate was next in line. In 1844, Willie Mangum was one heartbeat away from the presidency.

So what? Well, I think we can come up with some interesting consequences without straining credibility too much. How about no US annexation of Texas? An earlier US civil war? Maybe an independent California? Maybe even other political entities like a Mormon Utah or an independent Hispanic New Mexico?

So how do we end up with President Mangum? Maybe slightly altering this incident would do the trick:

“The last year of Tyler's presidency was marred by a freak accident that killed two of his Cabinet members. During a ceremonial cruise down the Potomac River on February 28, 1844, the main gun of the USS Princeton blew up during a demonstration firing. Tyler was unhurt, but Thomas Gilmer, the Secretary of the Navy, and Abel P. Upshur, who had succeeded Daniel Webster at the State Department nine months earlier, were instantly killed.” (Wikipedia)

So the freak accident kills Tyler as well as his cabinet members. What does that do?

No US Annexation of Texas? Texas had been an independent republic for nearly a decade by 1844. Texans wanted to join the US. Southern slave owners wanted Texas to join the union to enhance southern power compared to the northern free states. Northern states opposed annexation because they were afraid of that result, and also because they knew that annexing Texas meant war with Mexico.

President Tyler made annexing Texas his top priority and the centerpiece of his failed campaign to gain reelection. He was the first vice president to gain the presidency due to the death of his president, and there was enough ambiguity in the succession laws that many in the Senate and Congress felt that he shouldn’t really be president so much as a kind of caretaker until a new president was elected. Tyler moved aggressively to gain the powers of an elected president, but was still regarded by many as “Your Accidency”. Tyler took a festering situation in the Texas annexation issue and inflamed it, finally pushing through an annexation resolution just before he left office, and setting in motion the chain of events that lead to the Mexican-American war.

Would Mangum have pursued that same policy? Probably not. He was a Whig from North Carolina, in a Whig party that was very vulnerable to the sectional resentments that Texas annexation would make worse. Even if he did pursue annexation he wouldn’t have time to develop the kind of power that Tyler had.

Let’s say that Texas annexation is postponed. That doesn’t stop the wave of US settlers pouring into Texas and into the officially Mexican territories that historically became part of the United States after the Mexican-American war. There were already over a thousand non-Hispanic settlers in northern California by 1846, most of them Americans. The Mormon migration to Utah started in 1847, before the War with Mexico ended. It would have probably gone forward even without the war. The Mexican government had little power in the area, much of which was still ruled by Indians. Tribes like the Apaches and Comanchees would have indignantly denied that they were part of Mexico or that Mexico had any control over them.

If the Gold Rush happened roughly on schedule with California still officially controlled by Mexico and the northern part of it a power vacuum, things could get ugly in a hurry. Gold rush towns were pretty lawless anyway. Gold rush towns in an area with no significant legal authority anywhere near them could be even more interesting.

Let’s see. We have a Gold Rush and an immigration of up to 70,000 Mormons looking for a promised land. We have a power vacuum over a quarter of a continent. We have hoards of gold. We have intrigues between Mexican, American, British, and maybe even French and Russian nationals, some working for their governments, some looking to exploit the power vacuum for their own financial or power ends. Sounds like a great place to put a story and a truly awful place to raise a family.

Wouldn’t the US just move into the vacuum eventually? Probably, but having that happen too soon wouldn’t be anywhere near as much fun as I think we can have with this one. The big issue would be that the north was in line to gain a number of new states in the next several years, while the slave states had no room to expand without annexing Texas. An unlikely but fun possibility: the south decides that it will eventually lose parity in the Senate and attempts to secede in 1850 instead of a decade later. Of course getting to the point of a civil war would require an indecisive president like Buchanan. A more decisive president would have probably fought back before losing control of so much US territory. (Hopefully more later, but no guarantees)

 Note: About six months after I wrote this I saw an excellent set of alternate history essays online, one of which paralleled this one in many ways, though the author went a different way with the idea.  I misplaced the web address, but if you would like a different take on this idea there is one out there.