Sen. Hillary Clinton's margin over Sen. Barack Obama among Ohio likely Democratic primary voters has shrunk to just 4 points, 49% to 45%, on the eve of the state's primary, according to a new Quinnipiac poll.
On Feburary 14, Clinton held a 21 point lead; on February 25 she was 11 points ahead.
Key finding: "Obama has made gains in the last week especially among men and black voters."