How down-ballot Democrats did in Allegheny County compared to Harris

Allegheny County has long been a bastion of Democratic voters, and a key base of support for Kamala Harris on Tuesday. The Democrats running for Senate and the U.S. House of Representatives this year had a mixed record relative to the top of the ticket: One outperformed Harris with county voters, one did about the same and one underperformed her.

But Sen. Bob Casey was the only one of the three to lose his race–though narrowly. In general, Casey and Harris performed similarly across the county. Their vote margins were within 5% of each other in more than 98% of the county's precincts, although each had pockets of support where they outperformed the other. (The election results are preliminary and have not been certified. There are around 18,000 ballots that haven't yet been included in the county's vote totals, including more than 12,500 provisional ballots, more than 3,500 election-night ballots and nearly 2,000 overseas and military ballots.)

Casey slightly underperformed Harris in Pittsburgh's urban core, and in many of Allegheny County's wealthiest suburbs, including Fox Chapel, Pine, Marshall, Mt. Lebanon, Upper St. Clair and Sewickley.

Casey did better in many of the county's working-class river communities, particularly in the Mon Valley but also in municipalities that include Stowe and Neville Island. He had better margins in the most rural reaches of the county, such as Findlay, West Deer and Forward.

Congresswoman Summer Lee, meanwhile, underperformed Harris in about two-thirds of the precincts where they both appeared on the ballot. Lee did even better than Harris in some of the areas where Harris was already better than Casey – such as some neighborhoods in Pittsburgh's urban core and the North Side. Lee also did better than Harris in some Casey strongholds – such as Mon Valley towns like McKeesport and Clairton.

But Lee underperformed Harris by around 10 or 20 percentage points in Pittsburgh East End neighborhoods, which are noted for large Jewish populations. Lee has been criticized by some Jewish community members for her public pronouncements about the war in Gaza.

Lee also did significantly worse in the affluent suburb of Upper St. Clair (5 to 10 percentage points) and other suburbs like Bethel Park and Plum (about 1 to 5 percentage points).

Chris Deluzio, by contrast, outperformed Harris in about 75% of the county's precincts, with particular strength in river towns like Stowe and Robinson, as well as the eastern parts of Penn Hills and Harrison. But Deluzio's improvements were small, with his totals falling within 5% of Harris' vote share.in nine out of 10 precincts.

Deluzio did well in Aspinwall, where he recently moved from, but underperformed Harris in Fox Chapel, his new home. He also underperformed in Pine, where his opponent Rob Mercuri lives, as well as a couple of the municipalities nearby, such as Marshall.

Deluzio's district also includes Beaver County; Lee's district includes parts of Westmoreland County.