WATERVILLE — Just a day after Democratic voters agreed to postpone nominations for mayor, the only declared Democrat running for mayor announced she was switching parties and endorsed Mayor Nick Isgro on Tuesday night at the Republican caucus.

Karen Rancourt-Thomas, who had announced last week she was seeking the Democratic nomination, said after the caucus that Isgro had contacted her Tuesday morning, hours after the Democratic party had postponed nominations for mayor. She said she felt as though she had been kicked out of her own party, which prompted her decision to change parties.

“I am very proud to be a Republican today,” Rancourt-Thomas said to the few dozen Republicans gathered Tuesday night in City Council chamber in a meeting that lasted less than hour.

Rancourt-Thomas said she felt welcomed by the Republican party and said she will do everything she can to get her voter base to support the Republican candidates in Waterville. She said she wishes the Democrats and whomever they nominate for mayor well, but said they will have to do their own damage control. She said she has been a Democrat all her life, though she did run for mayor in 2014 as an independent.

“I will help elect every Republican in this room,” she said after the meeting.

After Rancourt-Thomas announced she was switching parties, Isgro said party members will embrace her.

“We are the big-tent party,” he said.

After Rancourt-Thomas’ announcement, resident Julian Payne addressed the crowd, saying he wholeheartedly endorsed Isgro, and called on every Democrat in the city to do the same and vote for Isgro. He spoke of the Democrats’ meeting the night before, which drew about 60 people, and said the party denied people the chance to vote for a Democratic nominee. He called the meeting “divided.”

“They said they needed more time,” Payne said. “They’ve had three years.”

Isgro, 35, will be seeking his second term as mayor. He was the only candidate seeking the Republican nomination. He announced his intention to run for another term on Facebook last week, stating that three years ago, Waterville started a movement to rise back up and form a new vision for the city. In his statement, Isgro cited “breaking down traditional barriers” and said partnerships with Colby College and others “have helped harness a vision that is now far beyond what we could have dreamed of two and half years ago.”

Isgro, just before the crowd unanimously selected him as the nominee, spoke of the good things happening in Waterville. He said $65 million is being invested into the downtown area, including $15 million of private investment. He mentioned that this fall, there will be new jobs downtown, as CGI employees will move into the old Haines building on Main Street.

“Things are on the move here,” he said.

His nomination drew a standing ovation.

According to the city clerk’s office, there are no term limits for mayor. Isgro first ran for mayor in 2014 in a three-way race, which he won with 2,470 votes. Democrat Stephen Aucoin had 2,047 votes in that race, while Rancourt-Thomas, who ran with no party affiliation, had 955. Rancourt-Thomas, a former city councilor, had announced she intended to run for mayor again this year, as a Democrat. She sought the party’s nomination at the June 10 Democratic caucus, but party members voted to postpone nominations for mayoral candidates. Democrats will reconvene at 6 p.m. July 26 to accept nominations for mayor.

Rancourt-Thomas called the postponement “atrocious” at the time. Tuesday night she said she felt warmly welcomed by the Republican party.

“This is where I am,” she said.

In his statement, Isgro said he wants to see through important “renaissance” initiatives in Waterville that involve multimillion-dollar investments downtown. Isgro is a controller at Skowhegan Savings Bank and treasurer of the Maine Children’s Home for Little Wanderers. He lives on Western Avenue. Rancourt-Thomas, 53, had said last week that she is running as Democrat “to bring together a city that is perceived as divided.”

Isgro was elected mayor after independent Karen Heck, who endorsed his first run. Heck followed Republican Paul LePage, who is now Maine’s governor.

Republicans also nominated Bob Hussey for councilor in Ward 2, defeating Phil Bofia, 12-6. For the Ward 2 School Board seat, voters selected Pat Roy over Zach Bickford, 10-3. Voters selected Sidney Mayhew, the incumbent, for councilor in Ward 4. There were no nominees for City Council Ward 6 or for School Board in Wards 4 and 6.

Isgro said the Ward 5 School Board seat and seats on the Kennebec Water District are available, but they mistakenly had not been advertised. He said interested candidates, if any, could email his office.

Colin Ellis — 861-9253

cellis@centralmaine.com

Twitter: @colinoellis