Italicized is my comments. Not part of the TL, per se.
The Ninth President,
Robert Delawney
Part One (Before Presidency)
Robert Delawney was a remarkable man, in a remarkable time. Born in 1791, in idyllic Georgia, to Adam Delawney, an cotton farmer (and slaver) and Mary Sweet, an Northerner who moved to the South in the 1780s. For this reason, he argued later in life, that he wasnt a Northerner, or a Southerner. He identified as "American" and nothing else. He took an interest in politics at the age of 17, and due to his not being an elder son (His older brother, Francis was born in 1787) they allowed him to start his career.
Robert Delawney entered politics properly in 1834, after a while supporting President Jackson's election campaign. Martin Van Buren, another Democrat, was in office at that time. He and Delawney got along well, with Van Buren saying "That Delawney, he is quite interesting." Delawney started by running for Senator of Georgia, but lost against John Pendleton King, an Jacksonian. However, when King resigned in 1835, another election was called, and Delawney won, finishing King's term.
Now, he wanted to be President, but how could he do it? The Governor of Georgia, William Schley, finished his term in 1837, and Delawney saw his opportunity. He ran for the Governorship, and got it. He served the full term, before resigning to run for the Presidency, as the Democratic Party's candidate, against the War of 1812 veteran, William Henry Harrison. Martin Van Buren denied to run.
Thus the timeline properly splits from OTL. Instead of Van Buren, we get Delawney, an completely new character, as the Democratic candidate. William Henry Harrison will live until 1851. The "Curse of Tippecanoe" will be called something different.