Facing growing concerns about his ability to win a Democratic primary next year, Rep. Jeff Van Drew (D-Dennis) asked Democratic county chairmen to sign a letter backing him for re-election.

The answer for many of them was no, the New Jersey Globe has learned.

“Some of us have had enough of Jefferson Van Drew,” one top Democrat told the Globe. “He’s on his own now.”

As a result, the letter never happened, according to six sources who spoke on the condition of anonymity.

Van Drew’s opposition to the impeachment of President Donald Trump has become a significant political liability in New Jersey’s 2nd district, where the progressive and moderate wings of the Democratic party appear united in their opposition to Trump.

That doesn’t mean Van Drew will necessarily lose party support as he prepares to seek a second term in Congress, but it is unusual for county chairmen to refuse to automatically endorse an incumbent.

Van Drew announced on Thursday that he planned to vote against impeachment, despite a plea from Atlantic County Democratic Chairman Michael Suleiman that he vote for it.

That might be enough to cause Brigid Callahan Harrison, a well-known political science professor who lives in the district, to enter the race.

A former secretary of the Atlantic County Democratic organization, and a freeholder candidate in the 1990s, Harrison has been mulling a challenge to Van Drew since he became one of two House Democrats to oppose the impeachment inquiry.

Harrison has a strong network of contacts throughout the state that could help her raise enough money to compete against the freshman South Jersey congressman.

Some lesser known candidates have also been mentioned, including a Cumberland freeholder and a local official from a tiny Cape May municipality.

New Jersey hasn’t ousted an incumbent congressman in a primary election for non-redistricting reasons since 1958, when Hudson County Democrats pulled party support for Rep. Alfred Sieminski (D-Jersey City).

Sieminski won a fourth term by just 57 votes against Republican Norman Roth in 1956 and his weakness as a candidate caused Democrats to abandon him.

He finished third in a four-candidate Democratic primary with 14% of the vote against former Hudson County Freeholder Cornelius Gallagher (44%) and State Sen. James Murray (36%).