YORK, Pa. — It’s fitting that Pennsylvania is land of the pretzel — where “Pennsylvania Dutch” Swiss and German immigrants introduced the food to America in the 19th century. Citizens of nearby Philadelphia reportedly consume 12 times the national average of the twisted, baked delight.A gas station here has pretzel sandwiches and inexpensive bags of broken pretzels. Both are metaphors for what is happening politically to Democrats here, to President Barack Obama in Washington, and to the Democratic Party around the country.