When the Democratic candidate Conor Lamb began his race in a special election in Pennsylvania’s 18th congressional district, he faced headwinds of the type that caused horizontal snow in the nor’easter last week.

For starters, Donald Trump had won the district by 20 points in 2016. The district has been held by Republicans for most of the last 50 years. Conservative “super PACS” were willing to spend millions — it ended up being around $10 million — to buy TV time to savage Mr. Lamb.

The incumbent, Tim Murphy, a conservative anti-abortion Republican, had a lock on re-election until The Pittsburgh Post-Gazette reported last year that he had urged his mistress to have an abortion. Republican House leaders decided that Mr. Murphy had to go. He resigned in October.

The man Republicans chose as their candidate was Rick Saccone, a Jurassic-era conservative who boasted that he was “Trump before Trump was Trump.”