MT. LEBANON, Pa. — One of the biggest advantages Conor Lamb had in his victory last week in the special election for Western Pennsylvania’s 18th Congressional District was that his campaign manager lived in his district.

Abby Nassif Murphy did not have an office at the Democratic Congressional Campaign Committee; she did not hold daily meetings with fellow Democrats in the Beltway who, on average, are fairly progressive both culturally and politically. She understood the heartbeat of the district not because of polls and data, but because she spends the bulk of her time carting her sons to and from their activities.