The district had 175,482 registered voters as of December 1, 2021[update], of whom 66,134 (37.7%) were registered as unaffiliated, 56,254 (32.1%) were registered as Republicans, 51,594 (29.4%) were registered as Democrats, and 1,500 (0.9%) were registered to other parties.
New Jersey's 40th has gone longer without electing a Democrat than any other legislative district in the state, having never chosen one under the new district-organization system (in place since 1973) and being one of four districts in New Jersey to elect all Republicans (at the state level) in the 1974 Watergate Democratic wave.
Upon the creation of the 40-district legislative map in 1973, the 40th District consisted of western Bergen County running from Elmwood Park north along the county line to Ridgewood, then in addition to Ho-Ho-Kus and Midland Park, consisted of the larger municipalities in the northwest corner of the county. Following the 1981 redistricting, the 40th lost Elmwood Park, Ho-Ho-Kus, and Allendale, but picked up Upper Saddle River and the Passaic County boroughs of North Haledon, Pompton Lakes, Bloomingdale, and Wanaque. In the 1991 redistricting, Ramsey, Upper Saddle River, North Haledon, Pompton Lakes, and Bloomingdale were shifted to other districts, but Washington Township, Waldwick, Ringwood, and West Milford became a part of the district. Under the 2001 redistricting, the Bergen County portion of the 40th District became smaller only running along the county border from Ridgewood to Mahwah (plus Midland Park), but in addition to Ringwood and Wanaque, passed through the center of the county picking up Wayne and Little Falls and for the first time included Essex County by encompassing Cedar Grove and Verona. Mahwah and Oakland were eliminated from the Bergen County portion in the 2011 redistricting but Allendale, Ho-Ho-Kus, and Waldwick were added, more of central Passaic County was added including Totowa and Woodland Park, and Morris County's Pequannock were included within the district.
Since 1973, the district has always leaned Republican, never electing a Democrat through the 2023 general election. It is one of only nine state legislative districts statewide that has never elected more than one political party to Trenton, and with the election of a Democrat to the 16th in 2015, the only district to have elected only Republicans.
Assemblyman DePhillips, a former mayor of Wyckoff, is the newest of the three in office, serving in the district since January 2018. First elected in 2017, DePhillips replaced David C. Russo of Ridgewood, who was first elected in 1989 and served until he left office in 2018 after his fourteenth term.
In 2023, the Republican ticket of incumbent Chris DePhillips (seeking his fourth two-year term) and Essex County GOP chairman Al Barlas ran against the Democratic team of Giovanna Irizarry (the Woodland Park school district's director of special education) and Wyckoff small business owner Jennifer Marrinan for two seats in the general assembly; meanwhile, Hawthorne school board member Jennifer Ehrentraut ran as a Democrat for state senate against Republican incumbent Kristin Corrado. In New Jersey all state legislature seats were up for re-election in the 2023 cycle.
Following Al Barlas making public his intention to run, Wyckoff's Kevin Rooney decided against seeking re-election to his position representing the 40th district in New Jersey's general assembly; the New Jersey Globe asserted that Rooney's decision was due to redistricting including six more Essex County towns in the 40th than previously (a process that Barlas co-chaired), thus meriting a representative from the county. In January 2023, just two months after announcing his candidacy, Barlas, "...raised a mammoth $112,844...making the first-time candidate one of the top GOP fundraisers in the state"; meanwhile, Corrado had amassed $117,457 and DePhillips had $145,095 (including, in both latter cases, leftover funds from previous campaigns). If Barlas is elected, he would be the first South Asian Republican in New Jersey's legislature.
In July 2023, the New Jersey Building and Construction Trades Council (a representative body for, "...13 Local Building Trades Councils, more than 100 local unions and over 150,000 rank and file members,") revoked its endorsement of the Democratic assembly candidates, with its president, Bill Mullen, composing a letter that stated, “...we appreciate your support for New Jersey’s...union construction and allied trades...[but] the NJBCTC executive board met...and [unanimously] voted to endorse your Republican opponents in this year’s election...Please consider this communication a formal withdrawal of the NJBCTC’s endorsement". Democratic Bergen County commissioner Tom Sullivan (who was, at the time, also an IBEW union president) fought for Irizarry and Marrinan being endorsed whereas former Democratic Senate President Steve Sweeney (who was also, at the time, head of the state’s Ironworkers union) advocated for the Republicans being endorsed. Local media called the representative body's flip "a highly unusual move" and a "devastating blow for the two newcomers".
In October 2023, the Corrado-DePhillips-Barlas slate released a mailer where they boasted that, "...Corrado has led the charge to expose Murphy's deadly policies that cost thousands of...lives during the pandemic," that, "...DePhillips is pushing legislation to slash the state's oppressive tax on businesses," and that, "...Barlas is running to restore commonsense values to our local schools and empower parents to be at the center of their child's education"; later the mailer tied president Joe Biden to rising inflation (via a Fox News headline) and Phil Murphy to New Jersey schools not, "...tell[ing] parents about student gender choices," (by way of a northjersey.com headline), calling them "radical Democrats" under whose leadership, "Our economy is tanking, and our values are under attack".
In the November 2021 election, Republican senator Kristin Corrado (with 47,230 votes) won re-election to her second four-year term, fending off a challenge from Democratic Ridgewood deputy mayor Michael Sedon (who earned 30,237), while the slate of Republican assemblymen Kevin Rooney (with 46,004 votes) and Chris DePhillips (with 45,246) won re-election to their third full terms, defeating the Democratic team of Waldwick councilwoman Nicole McNamara (who earned 31,066 votes) and former assistant Bergen County prosecutor Genny Allard (who earned 30,606).
For 2021, The New Jersey State FMBA (a union representing career firefighters, EMTs, and dispatchers) backed the three Republicans in a slate of mixed Republican and Democrat endorsements, and the New Jersey Fraternal Order of Police (also in a politically-heterogenous round of endorsements) chose to support the three Republicans as well. Meanwhile, the three Democrats were endorsed by the New Jersey Democratic State Committee LGBTQ Caucus (to which the candidates responded that they were "humbly honored" as Democrats, "...who value equality for all Americans of every race, sexual orientation, and gender identity"); the Progressive Turnout Project endorsed the three Democrats along with 54 other New Jersey state-level progressives; and after, "Challengers...respon[ded] to [their] application and demonstrated support for women’s issues in their official campaign platform," the National Organization for Women of New Jersey PAC endorsed Democrat Genny Allard individually.
In the November 2019 election, Republican assemblymen Kevin Rooney (with 22,562 votes) and Chris DePhillips (with 21,955) won re-election to their second full terms, defeating the Democratic slate of former Bergen County Freeholder Julie O'Brien (who earned 17,557 votes) and Little Falls councilwoman Maria Martini Cordonnier (who earned 17,332).
In late October 2019, DePhillips and Rooney skipped a debate hosted by the League of Women Voters, claiming that the question-selection process was "broken" and "unfair" because an earlier debate sponsored by the Wayne League of Women Voters had allowed, "...a local Democratic candidate to be part of a group that was screening questions and determining what questions would be asked". DePhillips and Rooney claimed they had spoken to the League following the Wayne debate and that, "The LWV...agreed to not allow questions from elected officials from either party," but that the organization rejected other structural requests they had made — pushing the two candidates to back down. Cordonnier and O'Brien criticized the Republicans' absence, arguing that, “...refusing to engage with [us] shows a lack of respect for their constituents and their office...As an elected official, you need to answer for your record even if you don’t like the questions".
Ridgewood Councilman Micheal Sedon (alongside Cordonnier) won the Democratic primary to challenge DePhillips and Rooney in the general election, but Sedon dropped out of the race between June and September 2019; in September, Democratic County Committee members from district towns selected O'Brien to replace Sedon on the ballot.
In the November 2017 election, Republican state senator Kristin Corrado (with 33,495) defeated Democrat and Garfield city manager Thomas Duch (who earned 26,060) in a race for her first full four-year term in New Jersey's upper chamber; meanwhile, Republican assemblyman Kevin Rooney (with 31,170 votes) won election to his first full two-year term as his running-mate, a former Wyckoff mayor, Chris DePhillips (with 30,610) won a seat for the first time, defeating the Democratic team of Christine Ordway (who earned 27,092 votes) and Ridgewood-restaurant-owner Paul Vagianos (who earned 26,737). Following Election Day (on which he became governor-elect), Democrat Phil Murphy named Ordway to his transition team's healthcare board — a role which involved, "...policy analysis and [making] recommendations on...state issues and initiatives as the new administration prepare[d] to take office".
In October 2017, the three Republicans faced off against the three Democratic candidates in a forum hosted by the Bergen County League of Women Voters in Ridgewood. At the forum, the Republicans argued that, "...affordable-housing obligations should be left up to local governments...[and cited] the lack of vacant land as a hurdle to increasing affordable-housing stock," whereas Vagianos claimed affordable housing requirements should be handled by state courts and Duch said that such housing, "is not evil" while touting the presence of affordable units in Garfield, the city he managed; Rooney supported extending the two-percent yearly salary increase cap on police and firefighters to manage municipal expenses while the Democrats blamed New Jersey's public-salary/pension crisis on, "...Chris Christie, who they said underfunded the state pension system"; Vagianos and Ordway brought up funding, "...the Hudson Tunnel Project...a new commuter tunnel between New Jersey and Midtown Manhattan," arguing it, "...would be a boon to local real estate values and the economy"; and the Democrats said they were committed to, "...fully funding Planned Parenthood in the state of New Jersey," in part in an effort to make more accessible, "...preventive care services for low-income women across the state," — which DePhillips contended (while supporting preventative care) was a distortion of the situation, as, "...the issue 'is about abortion'," while Corrado pointed out that Planned Parenthood is not the only institution offering preventative care in the state.
In July 2017, Republican county committee representatives from 40th District towns selected Passaic County clerk Kristin Corrado to fill the remaining several months of what had been Kevin O'Toole's senate term until he resigned earlier in the month. Corrado's appointment came after she won a contentious primary in June (to be the Republican nominee for state senate in the general election), in which she and Paul DiGaetano (a former seven-term assemblyman and, at the time, the Bergen County Republican party chairman) were each supported by divergent segments of the District's Republican leadership.
In October 2016, Assemblyman Scott Rumana resigned with a year remaining in his term after being confirmed as a judge on New Jersey's Superior Court. In November, Wyckoff mayor Kevin Rooney was appointed (in a 104-96 vote against Mike Marotta) to fill the remainder of the unexpired term; according to The Record, Rooney’s appointment was, "clearly a blow" to local GOP leadership, as the contest, "...was seen as a proxy fight between rival GOP camps [considering that] Marotta had the backing of three county chairmen...[and was] a longtime Rumana ally [whereas] Rooney had the political blessing of [40th District state senator] O’Toole and the backing of Peter Murphy, the maverick GOP leader from Totowa...[and] enemy of Rumana".
^Cowen, Richard (July 26, 2017). "Corrado tapped to replace O'Toole in state Senate". NorthJersey.com. Retrieved October 5, 2017. Republicans in the 40th District on Wednesday selected Kristin Corrado to finish the unexpired Senate term of Kevin O'Toole, who resigned on July 1.