The 2018 midterms were cause for celebration for Democrats. Nationally, they captured control of the House with the help of a four seat net pick-up in PA while Governor Wolf and Senator Casey also won overwhelming re-election victories.

The seeds of these results could be seen in the voter registration gains Democrats made throughout 2017 and 2018. Conversely, the erosion of Democratic numbers in 2015 and 2016 portended Donald Trump’s surprise upset.

So how are things shaping up for 2020? Of course it’s very early, and efforts to update the rolls had a significant effect on these numbers, but the recent deadline for this month’s primary marks a good starting point to examine the next cycle. The following is a county-by-county tally of the net shift in voter registration from October 2018 to today.

A quick note: I explore our changing voter trends by tracking the gains one party accumulated in registrations over the other party. For example, R+500 means that the Republican Party gained a net 500 more registered voters in that county than the Democratic Party did over this time period while D+500 indicates the opposite.

Central:

Blair: R+427

Centre: R+501

Clearfield: R+738

Columbia: R+490

Huntingdon: D+458

Juniata: R+102

Mifflin: R+143

Montour: R+81

Northumberland: R+338

Snyder: R+136

Union: D+101

As you might expect, the GOP made solid gains throughout the heart of the commonwealth with the largest margin being R+738 in Clearfield County. Their best result, though, was the R+501 registration advantage they built up in Centre, a usually blue county thanks to Penn State. On the other hand, Democrats are beginning to reverse the tide in Union (D+101) and scored a small but surprising bump in Huntingdon (D+458).

North-Central

Bradford: R+37

Cameron: R+115

Clinton: R+279

Elk: R+519

Lycoming: R+666

McKean: R+210

Potter: R+34

Sullivan: R+51

Tioga: R+62

In 2015, two of these counties, Clinton and Elk, still had Democratic registration advantages. Yet over the past few years, Republicans have completely consolidated their support up here. The stats in Lycoming and Elk are particularly encouraging for the Pennsylvania GOP.

Northeast:

Carbon: R+579

Lackawanna: R+1,914

Luzerne: R+1,223

Monroe: R+753

Pike: R+14

Schuylkill: R+914

Susquehanna: R+103

Wayne: R+131

Wyoming: R+178

A solid case could be made that the biggest the biggest problem for Pennsylvania Democrats is the erosion of their support in the Northeast. Carbon County, which Democrats in 2015, is gone, and is likely never coming back. The real issue, however, is Lackawanna and Luzerne counties. The two counties have seen R+1,914 and R+1,223 gains respectively since last October. If Trump can replicate his 2016 performance in the Scranton/Wilkes-Barre corridor, flipping PA back into the blue column will prove quite difficult.

Northwest

Crawford: R+342

Clarion: R+354

Erie: R+576

Forest: R+41

Jefferson: R+219

Mercer: R+793

Venango: R+168

Warren: R+253

Mercer is yet another county the Dems have lost over the past four years. And that trend is continuing with Republicans adding on another 793 voters to their advantage. While losing that county isn’t fatal, the movement in Erie (R+576) is much more concerning for Democrats.

South-Central

Adams: R+344

Bedford: R+418

Cumberland: D+225

Dauphin: R+375

Franklin: R+589

Fulton: R+61

Lancaster: D+672

Lebanon: R+228

Perry: D+50

York: R+682

The long-term spot to watch is Lancaster County. Although Republicans still hold an overall advantage of R+62,280, statewide Democratic candidates continue to perform better there. In fact, South Central may be moving so fast that voter registration is a lagging indicator. Much as the Southwest started voting Republican years before its residents officially abandoned the Dems, the reverse may be happening here.

Southeast

Berks: R+1,930

Bucks: D+438

Chester: D+933

Delaware: D+2,103

Lehigh: R+1,668

Montgomery: D+212

Northampton: R+1,158

Philadelphia: R+8,638

Philly’s collar counties remain the most pivotal in all the commonwealth. So the good news for Democrats is that they gained ground in all of them, especially Delaware. The bad news is that the GOP put up some solid stats in the Lehigh Valley.

The closer the 2020 Democratic nominee can match his/her totals in Lehigh Valley to their performance in Southeastern Pennsylvania, the more likely they’ll emerge victorious. Finally there was a bloodbath in the City of Brotherly Love, likely a result of updating the voter rolls, which should serve as a reminder to the blue team that they can’t depend on Philly to do it all.

Southwest

Allegheny: D+3,554

Armstrong: R+533

Beaver: R+1,555

Butler: R+591

Cambria: R+2,268

Fayette: R+2,269

Greene: R+714

Indiana: R+530

Lawrence: R+925

Somerset: R+626

Washington: R+1,315

Westmoreland: R+4,536

We’re rapidly approaching the end of the Ancestral Democrats. Westmoreland and Lawrence switched in the past four years and the next four will see several other counties jump ship as well.

The one exception is Allegheny County, where the party has built their advantage to a strong D+288,266. It’s increasingly clear that unless you’re in a metropolis like Pittsburgh, it’s just impossible to be a Dem in Appalachia.

Conclusion

Overall, these results unfolded about how I expected them to. Republicans continue to dominate in rural areas while Democrats are picking up support in the more educated suburbs growing outside Pennsylvania’s major cities. The one surprise is the erosion of Democratic advantages in places like Dauphin, Erie, Lackawanna and the Lehigh Valley. While the heart of blue Pennsylvania remains the Acela corridor, Dems will still have to hold their own in cities like Reading, Erie and Scranton in order to flip those crucial twenty electoral votes back in November 2020.

Nick Field, of Bucks County, contributes to a number of publications including Pennlive, WHYY, City & State, PhillyVoice, and LevittownNow. His work appears occasionally on the Capital-Star’s Commentary Page.