She won the primary, but can she win over labor?

With a $2 million bankroll and heavy advertising, Elizabeth Esty won the high-profile Democratic primary for the 5th Congressional District. Now, she has to win a quieter, if still crucial campaign for the support of organized labor.

The first test will come Wednesday when the Connecticut AFL-CIO's political committee meets to consider transferring its backing to Esty from Christopher G. Donovan, the union favorite she defeated in a three-way primary.

Esty, who voted against labor on a handful of key items during her single term in the General Assembly, concedes she has little hope of defeating Republican Andrew Roraback in the highly competitive district without a unified Democratic base.

"I've been in a lot of conversations with folks in labor," Esty said. "It's very focused, as I am, on the critical importance of a Democrat winning that seat. Labor is absolutely critical to making that happen."

Right now, the support is not there - starting with Donovan, whose refusal to immediately endorse Esty carries several complications, not the least of which is that he can continue as the nominee of labor's Working Families Party.

Donovan pointedly refused to disavow running on the Working Families line after his loss Tuesday night, but a labor leader and some of his closest friends in politics say Donovan could only be a spoiler, a role they see him rejecting.

"There is no path toward a Working Families victory with a third-party candidate. I just don't see that. That's something that is not viable," said John W. Olsen, the president of the state AFL-CIO.

"Chris understands that," said a friend, one of several who asked not to be quoted by name, so they would not be seen as pressuring Donovan. "I haven't heard from any of his close friends saying, 'Let's get him to do this.' Or, 'We can do this.' "

Donovan, who is taking a few days off, has not informed the Working Families leadership of his intentions. The party has no mechanism by which it could strip a candidate of an endorsement.

"I think there is less conversation than waiting, frankly," said Kurt Westby, an Service Employees International Union leader who is co-chair of the Connecticut Working Families Party. "I haven't spoken to Chris."

Olsen, who is a former Democratic state chairman as well as head of the state AFL-CIO, a federation of autonomous unions, is pushing for a quick consensus around Esty, as is Gov. Dannel P. Malloy.

"We'll take Roraback's record and compare it to Esty. I'm pretty sure the decision will be to support Esty," Olsen said.

Donovan was the heavy favorite to win the nomination until his campaign was rocked by the arrest of two top staffers accused of conspiring to collect illegal campaign contributions.

Esty sought the endorsement of labor and the Working Families months ago, but she positioned herself as labor's second choice, knowing she could not compete with Donovan's labor record and his relationships.

Donovan, 58, of Meriden was a labor organizer before his election to the House 20 years ago. He was co-chairman of the Labor and Public Employees Committee before becoming majority leader and then speaker.

"I understand I need to earn their trust and support. Chris Donovan eared their support over 20 years of service to the state," Esty said. "I respect their loyalty and commitment to him. I need to do work to do this, and I understand that."

Esty, 52, of Cheshire established a voting record in her two years that is liberal by most standards. In her first year, she voted to repeal the death penalty, a risky vote in Cheshire, where feelings still were raw about a triple homicide.

She voted with Donovan and labor on three close veto overrides: two on health-care reforms, and the other a bill that set a standard wage and  extended health care coverage to janitors who clean state buildings.

During a fight over Pratt & Whitney Aircraft's closure of the Cheshire jet-engine plan, Esty worked closely with the International Association of Machinists, making some friends in the labor movement.

"They know me, and they know how hard I worked on these issues," Esty said.

But the Working Families Party is warier about Esty than is labor as a whole. Backed by some of labor's most progressive unions, the Working Families Party practices fusion politics, cross-endorsing candidates who almost always are Democrats.

"This is an opportunity to talk about values," said Lindsay Farrell, state director of the WFP.

One of its key issues was the support of a law mandating that many private companies offer paid sick days. Esty was one of 23 Democrats who voted against the bill in 2009, when it passed the House and died from inaction in the Senate.

Esty, who was defeated for re-election in 2010, says she supports a federal paid sick days bill and would have voted for the amended version that passed the legislature in 2011 with a push from the new governor, Malloy.

The bill was narrowed in 2011 to exempt manufacturers and YMCA and YWCA day-care centers, and any paid time off offered could be counted against the sick time requirement. It applies to businesses with more than 50 employees.

"The issue in my district was the YMCA. The Ys are the largest child-care providers in the country," Esty said.

The Working Families Party played a role in electing the first Democratic governor in 20 years. Without the 26,308 votes cast for Malloy on the WFP line, he would have lost to Republican Tom Foley, 560,874 to 540,970.

Now, if they deny their cross-endorsement to Esty, they could help elect a Republican.

Westby and Farrell said the Working Families will try to be pragmatic, without sacrificing their progressive principles.

"There is a tension between the practical considerations and ideological considerations," Farrell said. "Working Families is not going to go with the lesser of two evils."

In a separate interview, Westby said, "We're not going to be endorsing folks that don't have a minimum amount of support in terms of our issues. I'm not saying Esty doesn't necessarily fulfill that."