When everybody comes out to vote, (i.e. presidential elections) Pennsylvania’s a blue state. And at least in certain pockets, it behaves much like the northeastern liberal states the surround it, like New Jersey, Maryland, and New York. When it comes to taxation, however, it looks a lot more like Texas or Alabama. According to a report by the Institute on Taxation and Economic Policy, PA has the 8th most regressive system in the country, meaning the poor pay more of their income in state taxes than the rich do.
Compare that to New Jersey and West Virginia–not exactly a bastion of progressivism.
What gives? Pennsylvania has a flat personal income tax, so inevitably, the less you make, the more you pay, proportionally speaking. The other states that comprise the “top ten”–Washington, Florida, South Dakota, Illinois, Texas, Tennessee, Arizona, Indiana and Alabama–mostly either have no income tax or a flat tax.
The Philadelphia Post: When it Comes to Taxes in Pennsylvania, It's Good to be Rich