Democrats have won Pennsylvania in the last six consecutive presidential cycles. And increasingly, they've done it by racking up huge margins in the city of Philadelphia, winning the surrounding counties by a decent margin, and absorbing losses throughout the rest of the state, which may explain all of the visits by Hillary Clinton and her surrogates recently.
First Lady Michelle Obama came to La Salle University Wednesday, to urge several thousand mostly young people to register and vote for her husband's former Secretary of State.
"Trust me, Pennsylvania," said Mrs. Obama, "experience matters, preparation matters, temperment matters, and Hillary Clinton has it all-- she's the real deal."
Team Hillary has blanketed the city of Philadelphia lately, and for good reason.
Four years ago, Barack Obama beat Mitt Romney in Philadelphia by 492,000 votes. He added to that, a 123,000 vote margin in Bucks, Chester, Delaware and Montgomery counties.
Mr. Obama lost the rest of Pennsylvania; in all, 55 of 67 counties went red.
But his huge margin in Philly and the 'burbs, carried Obama to victory. St. Joseph's University political scientist Randall Miller puts it simply:
"If most of the votes are down here, then what you need to do, is do well down here."
Miller notes that Donald Trump is competing hard in the counties around Philly, and predicts he will do well-- very well-- in the more rural areas of central and northern Pennsylvania, where he says jobs-- and confidence in the system-- have largely disappeared.
"These people do want to make America great again," said Miller. "They want an America in which they count. They don't feel that way right now, and it's not just jobs- it's everything that relates to that-- a sense of real purpose-- that 'I'm the father. I can deliver things. My values actually count for something.'"
Can Hillary Clinton count on the landslide that Philly voters gave to Barack Obama? Polls suggest voters are unenthusiastic about Mrs. Clinton. Which may be why Mrs. Obama felt the need to include this line in her LaSalle speech:
"I'm inspired by her persistence, her consistency, by her heart and by her guts. And I'm inspired by her lifelong record of public service!"
Republican vice-presidential nominee Mike Pence comes to Pennsylvania Thursday, and-- in a nod to the importance of Central PA to the GOP-- will campaign in York.