Pundits are making a big deal out of #OH12 having been Republican for decades. When the incumbent steps down, the replacement wins the district by a far narrower margin or if the seat has a Democrat. Kasich, won the district 50-47 in 1982.
Pat Tiberi, the incumbent that stepped down, won the district 52.87-43.83 against Democrat Maryellen O'Shaughnessy. The seat was vacated by John Kasich during that election in 2000. Obama won the district 53% to 46% in 08. Bush won it against Kerry 51-49 (not exactly a blow out).
During those elections mentioned the country was far less divided than it is now. Media attention on a political party was not nearly as negative as it is on Republicans or the current president, Donald Trump. That makes a significant impact on a local election in the spotlight.
Recent reporting also showed that Balderson was outspent in the district, but we'll see what the reporting says after his win tonight. Also, a candidate has to win their race when it is hotly contested. An endorsement for a weak candidate will only give a small bounce
An endorsement for a strong candidate will go a lot further because it adds to the already existing momentum the candidate has. Democratic pundits/strategists will try to spin this loss, but a loss is a loss, doesn't matter if it is by one vote or a million.
