Biden is going to win Oklahoma County, putting an end to the streak of the (atlas) Blue Oklahoma county sweep map we see every election.
This sweep map has been ongoing since 2004, so a Biden victory in Oklahoma County would make him the first Democrat to win a county there since Al Gore twenty years ago. Even more importantly, he would be the first Democrat to win Oklahoma County in 56 years, since Lyndon Johnson did so in 1964 (which was also the last time Oklahoma voted Democratic in a presidential election).
At any rate, if Biden is carrying Horn's district, then she is almost guaranteed to win reelection. Such a result in Oklahoma would portend swings against Trump in urban and suburban areas elsewhere in the country, swings that would result in his defeat.
Horn appears to be underperforming the top of the ticket by a fair bit though.
https://projects.fivethirtyeight.com/polls/20200608_OK.pdf
