Why Democrat Jeff Van Drew broke ranks with on the impeachment inquiry vote

Well, for one, his district is in South Jersey.

Source:  Wikipedia

2.  Trump lost New Jersey by 14.1 percentage points but won the 2nd congressional district by 4.6 percentage points.

Sources:  CNN (NJ/US), Daily Kos ( 2nd CD)

3.  Trump also flipped a district that twice voted for Obama, by an average of nearly 8 percentage points.

Source:  Daily Kos

4.  Not to mention that the seat had been held by this guy....

...Frank LoBiondo, a Republican, from 1995 to 2018.

Meet the Democrats Who Broke Ranks on Impeachment.  (The New York Times, 10/31/2019)

Playing it coy all the way, with a little self-preservation on the side. “I don’t want to move the country further apart,” Mr. Van Drew told reporters after casting his vote. “We could investigate the issues that we’re really concerned about without going further down the impeachment road.”  

Predicting a successful impeachment in the House and a failed trial in the Senate, Mr. Van Drew added: “We’ll have the same president and presidential candidate who will be able to say he is exonerated. So I don’t know how much we really gain from that.”