AUGUSTA — Democrats say an upset special election win in a Republican-leaning Lincoln County Senate district shows voters are tired of GOP rule in Augusta.

Maine Democratic Party Chairman Ben Grant said Tuesday’s victory is indicative of a larger political shift beyond Senate District 20. Democrat Christopher Johnson of Somerville defeated Rep. Dana Dow, R-Waldoboro, turning the seat over to Democrats after nearly 10 years of Republican rule. The margin was 54 percent to 46 percent.

“Last night’s upset victory sent a loud and clear message to Augusta and the people of Maine,” Grant said during a State House news conference to celebrate the win. “The Republican majority is out of touch with Maine people.”

Dow, a well-known local business owner and moderate with House and Senate experience, said Democrats won because they ran against Gov. Paul LePage.

“I think there was a referendum on the second floor,” he said, referring to the governor’s office. “It was pure politics.”

Senate District 20 includes 19 towns in Lincoln County, two in Knox County and the Kennebec County town of Windsor. Turnout for the Valentine’s Day election was low, with about 6,270 votes cast, compared to 19,530 cast in the same district in the 2010 general election.

The low turnout was a factor in Johnson’s win, Maine Republican Party Chairman Charlie Webster said. He said he also believes Johnson worked hard and it paid off, but that the outcome in no way shows a shift in the electorate.

“That doesn’t change the fact that the next election will be about the welfare state,” Webster said. “If they want a welfare state, they will vote Democratic. If they want help for their families, they will vote Republican.”

Republican groups supporting Dow spent more than $26,000 on the race, while Democrats spent about $6,200, according to campaign finance reports. Grant said a Democratic win despite being outspent 4-to-1 is another indication of the frustration among voters.

The win doesn’t change the balance of power in the Senate, leaving Republicans with a 19-15-1 advantage. University of Maine at Farmington political science professor Jim Melcher called the win interesting, particularly in light of Dow’s name recognition in the district; but he said it’s dangerous to read too much into one Senate race.

“Saying from one election that voters are voting to repudiate Augusta is a bit of a stretch,” he said.

Unofficial results released by Democrats, and updated by the Kennebec Journal, give Johnson a 466-vote margin of victory with all precincts reporting. The totals show 3,368 for Johnson and 2,902 for Dow.

Johnson is expected to take his Senate seat today.

Dow, a current House member and former state senator, was widely seen as the favorite to win the seat that was vacated late last year by Sen. David Trahan, R-Waldoboro.

Dow, who runs Dow Furniture in Waldoboro and Augusta, addressed the House chamber Tuesday, thanking his supporters and reiterating his intention to continue to serve in the House.

Johnson, 55, is a director of information technology for DeskNet, a technology company based in Portland and Jersey City, N.J., and is a former employee of Central Maine Power Co. When he first ran for the Senate seat in 2010, he finished a distant second to Trahan in a three-way race.

Johnson represents Somerville on the board of directors for Sheepscot Valley Regional School Unit 12 and served on the Lincoln County Regional Planning Committee. He has been the moderator for Somerville’s annual Town Meeting for many years.

“What I heard from constituents while knocking on thousands of doors this winter was the Legislature needs to focus once again on the real problems most important to Maine people,” Johnson said. “Getting people back to work, and creating jobs that keep our kids in Maine.”

He said he also heard from voters that it’s important to take care of senior citizens and the poor without “pitting one group of Mainers against another.”

Susan Cover — 620-7015

scover@mainetoday.com