In 1840, John Tyler's political career seemed to be over.
After his resignation in 1836, he had broken with Andrew Jackson's Democratic party, which had caused him to gravitate to their opponents the Whigs.
But Tyler didn't like much of the Whig platform either, which was dominated by Senator Henry Clay of Kentucky.
Clay considered one of the 19th century's most brilliant politicians was the champion of centralization, having been an architect of the Second Bank of the United States.
And when Andrew Jackson successfully killed it in 1836, Clay vowed that he would start another one.
1840 was the great chance for the Whigs to seize power and make Clay's dreams a reality.
The country had been gripped by an economic depression since 1837 and many blamed Democratic President Martin Van Buren and his party's fiscal policy for it.
At the party's nomination convention in Harrisburg, the Whigs eventually settled on General William Henry Harrison as their candidate for president.
But who would be his running mate?
Nobody seemed to want the job of being vice president and it isn't hard to see why.
It was considered a political dead end.
In those days, VPs had little to do besides preside over the Senate and they only voted in that body when there was a tie to break.
And it wasn't seen as a natural stepping stone for the presidency either between 1800 and 1968.
Only one man who had previously served as vice president had been elected president in his own right.
After several verbal candidates turned them down, the Whigs turned to Tyler who accepted and the ticket was complete.
The Whigs won big in the 1840 election, backs of Tippecanoe and Tyler, too.
A popular campaign slogan that referred to General Harrison's famous victory in the Battle of Tippecanoe in 1811.
Not only did they win the White House, but they swept majorities in both houses of Congress as well.
Henry Clay believed he had a mandate from the American people to enact his legislative agenda.
And nothing appeared to stand in his way.
But they was about to change the course of American history.
On the 4th of April, 1841, only a month after being sworn in his vice president, John Tyler woke up to a knock on his door in the middle of the night.
The news he received was grave, President Harrison was dead at the victim of pneumonia.
He was needed in Washington immediately.
This was the first time that the constitutional line of succession needed to be used and it immediately provoked confusion.
No one was sure if John Tyler assumed the office of president upon the death of William Henry Harrison, or if he remained vice president and merely assumed the duties of president until a new one could be elected.
Constitutional confusion was averted when Tyler himself decided that he was now the president.
He took the oath of office the next day, and for the rest of his life, he would return all mail that addressed him as Vice President Tyler or acting President Tyler unopened.
This set a precedence in the seven subsequent cases where a president died and off as the vice president has taken over after taking the oath of office.
The line of succession was eventually clarified with ratification of the 25th Amendment to the Constitution in 1967.
Still, it wasn't all smooth sailing for John Tyler for the rest of his term.
His opponents derided him as his accidency because of the way that it assumed the office.