Hillary Clinton has a good chance of sweeping the Keystone State. Katie McGinty might even take out sitting Republican Sen. Pat Toomey. But further down-ballot – much further – suburban and rural Democrats are preparing for a veritable electoral apocalypse.

Democratic sources say they’re fretting over the possible loss of as many as five state Senate seats – and that Senate Minority Leader Jay Costa may be out of his leadership slot, if their worst fears are realized.

Insiders say one seat is virtually certain to fall to Republicans – the 35th district, which was given up by longtime incumbent John Wozniak earlier this year. Cambria County Controller Ed Cernic ran in his stead, but election watchers say his candidacy against Republican Wayne Langerholc may be doomed.

“I have not seen any (PA Democratic Senatorial Campaign Committee) money spent on the seat, and Mr. Cernic has not been featured in any of the Harrisburg fundraiser invitations I have seen,” said Jake Sternberger, a political strategist familiar with the district. “You know it’s not looking good when even the Johnstown Tribune-Democrat...backed the Republican state Senate candidate.”

And that's the sentiment prevalent among the optimists

Several Democratic operatives said four other seats in play may fall: Sen. Rob Teplitz (D-15, Dauphin County); Sen. Andrew Dinniman (D-19, Chester County); Sen. Sean Wiley (D-49, Erie County); and Marty Molloy, a candidate for an open seat in Delaware County.

While it’s unlikely that Democrats will lose all five – there is some hope that Molloy could even pull out a win against Republican Tom Killion – but the loss of even a few seats could give Republicans a veto-proof 60 percent supermajority in the state Senate.

“If the Republicans get 34 senators, they can override vetoes – that would be the most important impact,” said pollster G. Terry Madonna.

The current balance in the senate is 30-20, in favor of Republicans. 

The state Democratic party offered only a general rebuttal to questions about close Senate races.

“The party has dedicated significant resources to important state House and Senate races,” said Brandon Cwalina, deputy press secretary for the PA Democratic Party. “In spite of Republican gerrymandering, we've created the largest coordinated campaign operation in state history to help elect Democrats from the presidential level to our row offices and state Legislature.”

“Gerrymandering” was the watchword amongst many frustrated Democrats.

“There are only a handful of seats in the state Legislature that are being seriously contested,” said Dan Fee, a Democratic political operative. “And that’s because a lot of them were unchallenged on both sides. That is due, I believe, in part to redistricting.”

Fee blamed a 2010 redistricting push by Republicans for exacerbating already gerrymandered districts, although he acknowledged that Democrats were also complicit in safety-proofing legislative districts.

But the problem may go much deeper than politicized redistricting. New research from Willamette University suggests that political districts may be inherently biased against dense, urban centers – which are increasingly the locus points for Democrat votes in many states.