What would be the most likely outcome of William Henry Harrison not catching his death on Inauguration Day and serving out his first term in office?
I wouldn't be too surprised if a future Vice-President "discharg[ing] the Powers and Duties" of the Presidency, being a politician who enjoys power, would do the same thing with the same result.If he survives his Presidency the biggest change would be that the presidential succession would not be established. Since that pretty much resulted from Tyler taking up the presidency afterwards.
I'm not sure about Harrison's attitude on manifest destiny, but he wasn't opposed to the expansion of slavery - in fact, he'd advocated permitting slavery in Indiana Territory to encourage settlement! (There's a strange PoD...) So, I don't think he'd strongly oppose annexing Texas. One way or another, though, if it's still a live issue by the '44 election, that wouldn't be changed much. iOTL, Tyler didn't annex it until he was a lame duck.Internal policy might not change much from Tyler, but WHH might hold off from annexing Texas for a last hurrah as Tyler did. This might change the campaigns and outcome of the 44 election. And maybe delaying the Mexican American War a bit.
Well, what he would do is probably found in his Inaugural address where he pretty much said what he would do.
Whig this and that. Though, it appears that Clay was so eager to get his own due that it lead to him and Harrison having a fall out.