Ricky Dale Harrington's landslide loss to Republican U.S. Sen. Tom Cotton on Tuesday represents a high-water mark, thus far, for the Libertarian cause in Arkansas and across the nation.

In unofficial returns, with 2,545 of 2,575 precincts reporting, it was:

Cotton 787,542

Harrington 393,110

The former prison chaplain from Pine Bluff, thus far, had 33.3% of the vote. Two-thirds of the ballots were for Cotton, a first-term incumbent from Little Rock.

"It's a record for a Libertarian U.S. Senate candidate anywhere in the United States. Ever. So we're absolutely enthusiastic and appreciative of that showing," said Joe Bishop-Henchman, the national party chairman.

Brian Colas, Cotton's political director, said 66.6% is also a high water mark for an Arkansas Republican in a major statewide race.

[RELATED: Full coverage of elections in Arkansas arkansasonline.com/elections/]

"We wanted to break 60%. We broke 66%," he said. "We're thrilled."

Both sides fared well because they didn't have to split votes with a Democrat.

Josh Mahony of Fayetteville, the party's only candidate, dropped out of the race hours after the filing deadline. Dan Whitfield, a Bella Vista independent, failed to collect enough signatures to qualify for the ballot.

That left voters with just two options: Cotton or Harrington.

Until now, Alaskan Joe Miller was the top-performing Libertarian Senate candidate; he captured 29.2% of the vote when he ran in 2016.

Miller was well-known by voters -- he'd lost a Senate bid in 2010, despite winning the Republican Party nomination.

Harrington, on the other hand, was a political newcomer.

Despite having minimal name recognition and even less money, Harrington, 35, captured nearly as many votes in Arkansas as Democratic presidential nominee Joe Biden.

He easily outpaced other Libertarians on the Arkansas ballot, including the party's presidential nominee, Jo Jorgensen of South Carolina, who finished with 13,024 votes.

Cotton was leading in 72 of the state's 75 counties, but Harrington finished ahead in Pulaski, Jefferson and Phillips counties. All three are Democratic strongholds.

Hal Bass, a political science professor emeritus at Ouachita Baptist University, portrayed Tuesday's vote as an aberration.

"It was just a protest vote by Democrats," he said.

"That does not indicate that there is a Libertarian constituency of that magnitude in Arkansas. It does indicate that there's an anti-Cotton constituency of that magnitude in Arkansas," he said.

Harrington, who could not be reached for comment Wednesday, fared relatively well despite being heavily outspent.

His campaign had collected $68,191 as of Oct. 14; Cotton had collected more than $12.8 million.

Harrington surpassed the most recent pollster's predictions.

A Talk Business & Politics-Hendrix College survey Oct. 19 Monday showed Cotton winning, 62% to 27% with 10% undecided.

The Arkansas Poll, released Oct. 28, had Cotton even further ahead, 75%-20%.

Cotton's internal polling had pointed to a closer race. In the closing days, he made repeated trips to Arkansas, while also working elsewhere to push for continuing Republican control of the Senate.

Rather than criticizing his opponent, Cotton talked about his own record and priorities.

"The campaign knew that the vast majority of Arkansans agreed with Sen. Cotton on the issues, so that's what our campaign prioritized," Colas said.

In addition to campaigning in Arkansas, Cotton also campaigned for vulnerable Senate colleagues, making stops in Georgia, Montana, Colorado and elsewhere.

Most of the candidates he backed ended up winning.

Read more here:

Cotton win good news, say parties of 2 rivals - Arkansas Online