In those days the Democrat party was a coalition between Southerners and northern immigrant populations — groups which didn't always agree with each other, and which wily politicians like FDR, would try to reconcile by, in this example, slipping out the White House's back door to avoid embarrassment.
Then as now, many non-religious Jews (i.e. “Punch” Sultzberger) were loyal Democrats first, and Jews second (or third, if at all) in their political orientations.
Today, many observant Jews (Mark Levin to cite one) are similar to practicing Christians in their politics — conservative, Republican, pro-Isreal.
And today's versions of old Sultzberger, like lemmings, blindly follow Democrat party lines, even to the detriment of Israel.
Ol’ Punch felt so Jewish, he married and raised his children Episcopalian.