Michael J. Zink stood five rows behind Barack Obama in November, listening to the president speak about the United States as a “nation of immigrants.” As an officer of the Advocates Society — a Polish-American bar group — he was a fitting audience member for Obama’s speech at the Copernicus Center in Jefferson Park. He received the choice seating assignment from connections he made working on Obama’s 2008 presidential campaign. What lessons did Zink pick up during that experience?  …