In deep blue New Haven, where Democrats hold every elected office, ideological consensus has come to prevail on the Board of Aldermen.

But the solidifying power of organized labor in successfully electing candidates for municipal office has tested that proposition, even for local lawmakers who declare themselves sympathetic to union interests. Seven alders — three of them in their first term — have formed a coalition designed to counterbalance the political sway of Yale’s UNITE HERE unions, Locals 34 and 35. Its members have provisionally termed the group the “people’s caucus” and will seek the input of city residents at its first public meeting on Jan. 25.

The caucus counts among its members two alders specifically recruited by UNITE HERE who say they now wish to cut ties with the unions that helped get them elected: Claudette Robinson-Thorpe in Ward 28 and Brenda Foskey-Cyrus in Ward 21. Robinson-Thorpe was first elected in 2009. She won re-election in 2011 along with a slate of 19 other labor-backed alders, including Foskey-Cyrus, who displaced candidates backed by City Hall.

“During my second term I soon realized that I had left one master for another,” Robinson-Thorpe said in a statement. She said she had traded her legislative independence for membership in a team of alders led by Board President Jorge Perez, UNITE HERE organizer Gwen Mills and former Ward 3 Alder and Democratic Town Committee Chair Jackie James.

Robinson-Thorpe argued that the UNITE HERE’s electoral influence has forged a new political machine — akin to the Democratic Party machine it sought to replace — in prescribing which way alders vote and promising retribution for not toeing the labor line.

“By making this statement I was told I would be committing political suicide and the Unions would run someone against me,” Robinson-Thorpe added.

The two union breakaways are joined by Ward 7 Alder Doug Hausladen ’04 and Ward 30 Alder Carlton Staggers as well as a handful of freshly minted alders: Anna Festa in Ward 10, Richard Spears in Ward 12 and Mike Stratton in Ward 19.

Hausladen said the caucus will hold monthly public meetings both to educate residents about the function of the Board of Alders and to give them greater voice in the legislative arm of their government. He said he does not foresee substantive disagreement with the majority of labor-backed alders but envisions the caucus as a progressive alliance with an ear to voices currently left out of political decision-making in New Haven.

A focal point of the group’s criticism is the Board’s vote in the summer of 2013 to sell portions of High and Wall Streets to Yale for $3 million. Robinson-Thorpe and others allege that union representatives sought to strong-arm alders into voting for the deal, which passed 21-8. Perez, who voted for the sale along with Robinson-Thorpe, denied that the blue-and-pink-collar unions exerted undue influence. He cited Foskey-Cyrus and Ward 20 Alder Delphine Clyburn as labor-backed alders who voted against the street deal.

Perez said Robinson-Thorpe’s animosity is personal: that she is lashing out after her unsuccessful bid for president pro tem, a leadership position second to the president of the Board.

At the Board’s first meeting of the new legislative term last week, Robinson-Thorpe mounted a last minute, unsuccessful challenge for the Board presidency instead. She lost in a landslide to Perez, who has held the position since 2012. Ward 23 Alder Tyisha Walker was elected president pro tem.

Ward 1 Alder Sarah Eidelson ’12 dismissed the caucus as the result of “personal disagreements,” which she said distract from the substantive work of the Board. Eidelson’s own union affiliation — namely her employment as a graphic designer for Local 34 — was a source of contention during her 2013 re-election race against Republican challenger Paul Chandler ’14, who focused on union ties rather than party label as the deciding question of the election.

“My decisions on the Board are based on the interests of my constituents,” Eidelson said.

Perez said the same: “I feel we owe our constituents. That’s it.” He added that nearly all of the Board’s votes have been unanimous, demonstrating alders’ common commitment to the legislative agenda they set at the beginning of the 2012-’13 term. Shared progressive principles mean the alders fall into lockstep on most policy questions, he added.

“Do we support some of the issues that some of our unions care about like safe streets and schools? Of course,” Perez said.

Local 35 President Bob Proto said he sees the unions’ job as “supporting the Board of Aldermen.” He said the union hears input from its members about the same issues that the Board is working to tackle, including jobs and public safety. He said he has never seen and has no knowledge of union leadership strong-arming elected officials.

Neither Mills nor Local 34 President Laurie Kennington ’01 returned requests for comment Sunday or Monday.

Mayor Toni Harp ARC ’78 — a former New Haven alder and state senator elected last autumn with broad labor backing, including the financial and vote-pulling support of Locals 34 and 35 — said she sees the disagreement as healthy for democracy. She said coming from the Connecticut General Assembly, where “we actually have Republicans and Democrats,” has taught her that a diversity of opinion furthers in-depth discussion.

Foskey-Cyrus said it is precisely room for discussion that the caucus aims to promote. Fidelity to labor, she added, means that votes are set from the outset, decided in consultation with the unions rather than in the Board’s chambers in City Hall.

In elections for leadership of the Board’s black and Hispanic caucus Monday evening, Robinson-Thorpe lost to Ward 6 Alder Dolores Colon ’91 for chair and to Clyburn for vice-chair.