After the confusion of 1800, the US amended it's constitution to ensure that Presidential electors vote for one Presidential ticket. Simultaneously, President Jefferson privately expressed support for abolishing the electoral college altogether. His argument was essentially the same as those often heard today: the EC is undemocratic because it takes what should be the peoples' right and hands it over to a small minority of delegates. Given Jefferson's immense political influence and public stature, had he pushed for an end to the EC there was a chance he could have gotten it.
Here is the POD: In 1796, after a few votes are shifted in PA and MD, Adams wins the Presidency without the popular vote. Jefferson feels cheated and eight years later the 12th Amendment provides for a unified Presidential ticket and an end to the EC. What if, since 1804, the US has direct elections for the Presidency?