The U.S. Senate race is tightening with the top Republicans and top Democrats in a virtual dead heat, according to a poll scheduled for release on Wednesday.

“This is literally going to be a barnburner,” Baton Rouge pollster Bernie Pinsonat of Southern Media & Opinion Research said Tuesday night. “It shows significant movement from what we found a few months ago.”

In another of the survey’s findings, Gov. John Bel Edwards received good job performance from almost two-thirds – 63 percent – of the 500 likely voters questioned. In the nine months since his January inauguration, Edwards has had to deal with massive budget deficits; the police shooting of an African American man and the protests that followed; the murder of three law enforcement officers; and historic flooding. The poll carries a 95 percent certainty level that the results would be no more than 4.4 percent off if all likely voters in the state were questioned.

Southern Media did the phone survey for its subscribers and was not paid by a candidate or special interest, Pinsonat said.

It’s the findings in the Senate race that Pinsonat found most intriguing even though slightly more than one-fourth of the electorate – 26.2 percent – was undecided.

The 24-candidate race to replace Sen. David Vitter, R-Metairie, who is stepping down at the end of his term, has attracted little attention with only 49 days left before the Nov. 8 primary.

“It’s not going to be quiet anymore,” Pinsonat said.

Longtime State Treasurer John Kennedy, a Madisonville Republican, had long been considered the frontrunner, scoring well over 20 percent favorable in early polling, far ahead of his opponents. But U.S. Rep. Charles Boustany, a Lafayette Republican who represents Acadiana in Congress, eroded that lead and polled 15.2 percent to Kennedy’s 16.9 percent.

On the Democratic side, Caroline Fayard, a New Orleans lawyer, had 11.4 percent support to 9.2 percent for Public Service Commissioner Foster Campbell, of Bossier Parish, according to the Southern Media survey.

When asked who the voter would favor if the election were held today, Republican Congressman John Fleming, of Minden, came in at 8.3 percent, and Rob Maness, R-Madisonville had 3.3 percent of the vote in the poll. The retired U.S. Air Force officer came in third as a tea party candidate in the 2014 Senate contest.

Former state representative David Duke, a white supremacist who says he advocates for the rights of European Americans and waged strong but losing efforts for statewide office in the early 1990s, was favored by 3.1 percent of the voters.

Pinsonat said Boustany’s showing reflects that he is the only major candidate running from Acadiana. Fifty-four percent of Boustany’s 3rd Congressional District constituents favor him in the Senate race.

Kennedy’s biggest support is in Baton Rouge-based 6th Congressional District, where 32 percent of those polled back him. Kennedy was found to have done an “excellent” or “good” job as state treasurer by 62 percent of those questioned.

The questioning took place between Sept. 15 and Sept. 17, just as news of unsourced allegations that Boustany frequented prostitutes in Jennings were raised in a book. Boustany says the claims, which have not been independently verified, are lies.

Pinsonat said this poll doesn’t chart much of the public’s reaction. But he doubts the charges will have much impact unless the allegations receive more media coverage or are used by Boustany’s opponents. “Politicos are talking about it, but I’d be surprised if 10 percent of the public knows about it,” Pinsonat said.

Pinsonat attributed Fayard’s bump to the endorsement by New Orleans Mayor Mitch Landrieu. She scored 22 percent in the New Orleans-based 1st Congressional District to Campbell’s 12.5 percent.

But Campbell is being backed by a number of African-American elected officials and organizations in New Orleans that have proven to get out the vote in the past.

“The mayor’s endorsement showed up in this poll. But her lead may or may not hold on Election Day,” he said.

Campbell, a north Louisiana elected official since the early 1970s, did best in the 4th Congressional District, where he is favored by 15.5 percent of those polled. Fleming, who is the congressman in that district, was backed by 25.9 percent of his constituents.

Follow Mark Ballard on Twitter, @MarkBallardCnb.