U.S. Rep. Jeff Van Drew (R., N.J.) and Democratic challenger Amy Kennedy are in a “dead heat" in their closely watched campaign in South Jersey’s 2nd Congressional District, according to a new poll.

The survey released Friday by Stockton University showed Kennedy with a statistically insignificant lead over Van Drew, the Republican incumbent who pledged his “undying support” for President Donald Trump after switching parties late last year. Her edge over Van Drew is only one percentage point, 46% to 45%.

Just 6% of voters are undecided or wouldn’t name a preferred candidate, according to the poll.

Despite Van Drew’s long history as a conservative Democrat, and decades of winning elections with support from voters across party lines, the poll showed little such support. About 5% of Republicans support Kennedy, and 4% of Democrats back Van Drew, the survey found.

Independent voters, a key constituency in the sprawling district, favor Van Drew over Kennedy, 48% to 42%. The district covers all of Atlantic, Cape Cay, Cumberland, and Salem Counties, and parts of four other counties.

“The 2nd District is living up to its billing as a competitive swing district,” said John Froonjian, executive director of Stockton’s William J. Hughes Center for Public Policy. “Turnout in the final days of mail voting and how the few undecided voters break will decide the race.”

Van Drew’s party switch continues to impact the race, even beyond the blizzard of negative ads funded by outside Democratic groups. A majority of voters, 55%, said Van Drew’s switch affected their opinion of him, with 69% of those voters saying it negatively affected their view of him.

Joe Biden is narrowly leading in the district, according to the poll, 48% to 45%. The district voted twice for Barack Obama before swinging to Donald Trump in 2016.

About 57% of voters in the district have already cast their ballots, according to the poll. More than 3.1 million people in New Jersey have voted by mail overall, about 80% of 2016′s total turnout. The largest share of the early vote in the district is coming from Democrats, Froonjian said.

» READ MORE: Jeff Van Drew has been winning South Jersey elections for decades. Can he do it as a Republican?

The poll found that Van Drew, a former state lawmaker, is slightly better known than Kennedy, a former teacher who is married to ex-U.S. Rep. Patrick Kennedy. The Kennedys live in Brigantine, in vote-rich Atlantic County, while Van Drew lives in Dennis Township, in Cape May County.

Van Drew has slightly higher negative ratings than Kennedy, however, with 37% viewing him unfavorably, compared to 30% for Kennedy. Only 42% approve of Van Drew’s job performance in Congress, while 50% disapprove, the poll found.

Overall, the poll found what people living in deep South Jersey already know: that voters in the 2nd District “feel more positive about Trump than do voters in the rest of New Jersey, where there are strong negative feelings about the president."

The poll found support for Van Drew and Trump to be largely coming from white men and those without a four-year college degree. Kennedy and Biden are supported at higher rates by Black voters, women, and college graduates.

”The differences among respondents across gender and education were not quite as stark as race, but still evident,” said Alyssa Maurice, a Hughes Center research associate.

The poll of 676 likely voters, conducted from Oct. 22 to 27, has a margin of error of plus or minus 3.7 percentage points.