John Kennedy and Foster Campbell began a one-month sprint Wednesday in the winner-takes-all U.S. Senate runoff.

State Treasurer Kennedy begins with a big advantage heading to the Dec. 10 election.

He is the Republican in a red state where Republicans occupy every statewide office except governor, following John Bel Edwards’ long-shot victory last year.

Kennedy and the other Republican candidates in Tuesday’s primary won about 60 percent of the vote, while the Democratic candidates — including Campbell — won about 36 percent. In the 2014 primary, then-Sen. Mary Landrieu ran better by winning 42 percent.

Republicans have won the past two Senate elections in Louisiana with at least 56 percent of the vote.

“It’s a very steep uphill climb for Foster Campbell,” said John Couvillon, a Baton Rouge-based pollster and demographer.

Couvillon said an analysis of precinct returns showed that only 16 percent of whites voted for a Democratic Senate candidate on Tuesday, compared to 21 percent for Landrieu in 2014.

Turnout in African-American precincts was 7 percent lower Tuesday than the turnout in white precincts, he added, compared to 3 to 5 percent lower in the previous two presidential elections. The drop is significant because African-Americans would account for about 75 percent of the votes that Campbell could expect in the runoff.

To be sure, the political pros can be wrong, as President-elect Donald Trump stunningly showed Tuesday night.

Campbell, who represents northwest Louisiana on the five-member Public Service Commission, has proven to be a popular populist throughout his 40-year political career and has the continued support of Gov. Edwards.

Exactly how much political capital Edwards will invest in Campbell was uncertain on Wednesday. The governor’s office released a written statement only reiterating Edwards’ support for Campbell.

Another uncertainty was whether national super PACs would spend money in Louisiana to elect either candidate after steering clear during the multicandidate primary.

During a news conference Wednesday, Campbell vowed that as a senator he would “fight like hell and be outspoken.”

“I'll be on the right side, helping the people,” he added.

Kennedy ran first in the 24-candidate primary with 25 percent of the vote, while Campbell finished second with 17.5 percent, narrowly edging out U.S. Rep. Charles Boustany, a Republican who won 15.4 percent. Following them was Caroline Fayard, a Democrat, with 12.5 percent and U.S. Rep. John Fleming, a Republican, with 10.5 percent. In sixth place was Rob Maness, a Republican, with 4.7 percent, and in seventh was David Duke, a Republican, with 3 percent.

Turnout for the Senate election was 63.9 percent, according to Meg Casper, a spokeswoman at the Secretary of State’s office, while the presidential election turnout was 67.1 percent, or 1 to 2 percent below her office’s earlier projection.

Kennedy and Campbell are running as political outsiders, but both men have held office for years, Kennedy since 2000 and Campbell since 1976. Both have yearned to go to Washington. Campbell has run three times for the U.S. House and lost, while Kennedy is making his third attempt at the Senate. The winner will replace Sen. David Vitter, who chose not to seek re-election.

Kennedy seems likely to “nationalize” the campaign, much as Vitter did in 2010 and Sen. Bill Cassidy, a Republican, did in 2014, likening their Democratic opponents to President Obama and national Democrats.

“It would be hard to find two of the 24 candidates who are more different than me and Commissioner Campbell,” Kennedy said in an interview Wednesday. “He’s a liberal Democrat, and I’m a conservative Republican.”

The two men in the runoff present clear differences on major issues. Campbell supports legislation to strengthen equal pay for women, a higher minimum wage and Edwards’ plan to try to force oil and gas companies to pay to restore Louisiana’s coast. Kennedy opposes those views.

Campbell believes that humans are responsible for climate change, while Kennedy says the science isn’t clear.

Kennedy supported Trump for president, while Campbell favored Hillary Clinton.

Kennedy wants to repeal Obama’s signature health care legislation, while Campbell wants to “improve it.”

As often happens, the primary campaign has left bruised feelings. Fayard is still smarting over Campbell portraying her as a disloyal Democrat because her mother gave money to the McCain-Palin Republican presidential ticket in 2008. Campbell also broadcast an ad suggesting that Fayard played a role in the 2007-09 financial collapse because she was a young staffer at Goldman Sachs on Wall Street.

On Wednesday, asked whether she would endorse Campbell, Fayard said, “We will see.” She noted that Campbell had not called her to discuss the campaign and her possible support.

Fayard said Kennedy did call Tuesday night, leaving her “a nice and gracious voicemail message.”

Kennedy also called Maness and was “very courteous,” said Maness’ spokesman, John Mathis. Mathis added that Maness is not issuing an endorsement as he focuses on getting a position with the Trump administration.

Reached Wednesday, Boustany begged off on answering whether he would endorse Kennedy, saying, “I’m pretty exhausted today.”

Fleming did not return a phone call, but Kennedy said he called him, too. In all, Kennedy plans to call 21 of the 22 other candidates, with only Duke on his personal do-not-call list.

One of Fayard’s biggest supporters, Mary Landrieu, said that she has endorsed Campbell. “Happy to help him,” she said in a text. Her younger brother Mitch, who is New Orleans’ mayor, also said he will endorse Campbell.

Vitter issued a statement strongly endorsing Kennedy.

Vitter’s support could create an opening for Campbell to run against the unpopular senator, said Verne Kennedy, a Pensacola-based pollster, just as Edwards did last year.

Nonetheless, in a late October poll for a group of businessmen and women in Louisiana, Verne Kennedy found that John Kennedy, no relation, has several advantages. Kennedy had a favorable rating of 49 percent and an unfavorable rating of 16 percent, or a 3.2 to 1 ratio.

Campbell had a 29 percent to 17 percent favorable to unfavorable rating, or a less-optimal 1.7 to 1 ratio.

“Unless something unexpected happens to lower Kennedy’s popularity, there is little or no chance that Campbell can win the runoff,” Verne Kennedy said.

One potential wild card is that few voters seem to know much about either candidate, based on interviews with 25 voters in Jefferson and Orleans parishes, giving Campbell and Kennedy the opportunity to define the other.

“I just picked one,” said Joan Hagens, a New Orleans voter, unsure which one she had chosen.

“I picked the first Democratic name,” said Nathan Fetter, an event organizer in New Orleans.

Elizabeth Crisp of The Advocate Capitol News Bureau contributed to this report.

Follow Tyler Bridges on Twitter, @tegbridges.