TOMS RIVER, N.J. — The tables inside the hotel room were full and Andy Kim, the candidate responsible for filling them, was pleasantly surprised. It was a weeknight fund-raiser after all, rescheduled once already, for this relatively unknown Democratic challenger in a Republican district and a thick fog on Route 37 had obscured the tiny sign directing drivers to the hotel.
“Seven months before Election Day this is not normal, to be able to pack a room on a weekday,” he told a crowd of about 150 supporters, each of whom contributed at least $10 to listen to Mr. Kim and snack on donated croissants.
Ever since the election of President Trump, Democrats across the country have seen a predictable surge in energy among a base eager to take on the White House. What has been perhaps less expected is the uprising against the president coursing through more moderate suburbs, including many Mr. Trump won. Democrats buoyed by recent victories in Republican districts have lofty aims in suburban New Jersey as they work to wrest control of the House from the G.O.P., given Democrats’ surprise victories in Virginia, Alabama and, most recently, Pennsylvania.
In New Jersey, which has been described by Democrats and Republicans as the most suburban state in the country, the revolt has been especially muscular and has put into play Republican-held congressional seats that until this year had hardly been on the Democratic radar. Voters have grown increasingly angry with Mr. Trump, viewing many of his actions as damaging the state’s fortunes.
Under the new federal tax overhaul pushed by Mr. Trump, which severely limits the deductibility of local taxes and mortgage interest payments, over 10 percent of New Jersey households will see their taxes rise, more than any other state, according to the Tax Policy Center, a research group. And Mr. Trump has been adamant about blocking any federal funding for a new rail tunnel under the Hudson River that would ease travel for tens of thousands of commuters.
As a result, New Jersey has become a key focus of the party’s effort to win the 24 seats it needs to retake the House. National leaders, outside groups and statewide officials have launched a concerted effort targeting four of the five New Jersey districts held by Republicans, including the Third Congressional District where Mr. Kim is running.
Already, two Republicans — Representatives Rodney Frelinghuysen and Frank LoBiondo — have announced retirement, while a third, Representative Leonard Lance, has had his race declared a tossup by the Cook Political Report, a nonpartisan organization that analyzes elections.
Super PACs and labor groups are mapping out plans for New Jersey, though they are mostly waiting until after the party primaries in June before making official endorsements or announcements about resources devoted to the races.
“We view New Jersey House races as some of the best pickup opportunities in the country,” said Josh Schwerin, a spokesman for Priorities USA, one of the largest progressive super PACs, “and are keeping an eye on them as we decide where to play in the future.”
Still, despite the Democratic mobilization motivated by Mr. Trump, Democrats in New Jersey face a difficult road. Mr. Kim, for example, is seeking to unseat Representative Tom MacArthur, a wealthy self-funded Republican who has been so well entrenched in his district that the Democrats barely put up a fight in 2016. No matter the anger at the White House, Mr. MacArthur can count on strong support from reliably Republican areas like Ocean County and the Cook Political Report has continued to rate the district as “likely Republican.”
But all those headwinds have not dampened the enthusiasm or financial support for Mr. Kim’s long-shot effort in this district, which cuts across the southern part of the state, from Burlington County to Ocean County. As of April 1, the first-time candidate with a background in national security has raised over $1.1 million with donations trickling in from all 50 states.
Mr. MacArthur does have some vulnerabilities, having voted with Mr. Trump more often than anyone else in the state’s delegation.
In the Third District, some voters say their dislike for Mr. Trump has colored their view of Mr. MacArthur, who voted in favor of the tax law and was instrumental in the Republican effort to repeal the Affordable Care Act.
“My problem with MacArthur is that he’s not protecting us, with health care and taxes and guns, he’s doing affirmative damage to me and this district,” said Susan Lavine, 64, a small-business owner from Moorestown, N.J. Ms. Lavine said she voted for Mr. MacArthur in the past two elections because, “I thought he was a moderate.” But she has since changed her mind and is now supporting Mr. Kim.
Despite Mr. MacArthur’s support for the tax bill and his opposition to the affordable care act, his campaign said that his voting record has tended to be more moderate and that his work on local issues, such as financing for a military base in the district, will mean more than the political polarization fomented by the Trump White House.
“Those are the kinds of issues that voters in Burlington look to as to what defines moderate for them, as opposed to some group in Washington,” said Chris Russell, a strategist for the MacArthur campaign.
Mr. MacArthur’s political team also noted that the Republican who lost to Gov. Philip D. Murphy last year, Kim Guadagno, won the district by the same margin Mr. Trump did in 2016, which Mr. MacArthur’s campaign said shows that the district remains loyal to the G.O.P.
National Republicans are also confident that when the election gets closer, and the stakes of the local elections become more clear, enthusiasm will ramp up among their base. And in New Jersey, they argue, the familiarity of the incumbent on a local level could be an advantage, as opposed to the relative unknown of someone like Rick Saccone, who lost in the Pennsylvania special election last month.
“Having your own brand, and having people know who you are is extremely important,” said Matt Gorman, the communications director for the National Republican Congressional Committee. He said well-known incumbents are also able to run on issues, rather than simply against the president, as they work to galvanize voters. “That’s why people like Lance and others were able to win seats in districts that Clinton won in 2016,” Mr. Gorman said.
Nonetheless, Mr. Kim has enjoyed widespread support, including the endorsement of former Vice President Joseph R. Biden Jr., underscoring the shifting political dynamics in New Jersey.
For the first time in about a decade, the Democratic Congressional Campaign Committee is focused on more than two Republican-held seats, its typical strategy, and is taking aim at all five, though the seat held by one Republican, Chris Smith in the Fourth Congressional District, is considered safe.
Mr. Biden announced recently that he was also endorsing Mikie Sherrill, the Democrat running in Mr. Frelinghuysen’s district.
In the 11th district, Ms. Sherrill has attracted national attention with her impressive biography — a former Navy helicopter pilot and a former federal prosecutor — and she has raised more than $1.2 million in 2017 alone. In the Second District, which Mr. LoBiondo held for more than 20 years, Jeff Van Drew, a state senator, has quickly attracted the endorsements of major statewide political players, including George E. Norcross, a powerful South Jersey power broker.
Besides a national mobilization to win Democratic seats in New Jersey, candidates are also benefiting from Mr. Murphy’s determination to strengthen his party’s dominance in the state. He appointed the former finance director of his campaign, Liz Gilbert, to be the state Democratic Party’s executive director and he has directed the state party to invest more heavily in this year’s elections than it customarily would.
“He didn’t want that to end in November when he won election,” Ms. Gilbert said of Mr. Murphy’s desire to keep his political machine cranking. “He wanted it to be part of his governing as well.”
At the fund-raiser for Mr. Kim, the optimism that the state’s suburbs were tilting in the Democrats’ favor was palpable.
“In Toms River, where it’s totally Republican all the time, Democrats just picked up three council seats,” said Barbara Ann Reilly, the president of the Brick Democratic Club, referring to elections last year. “I even had a group of Republicans that came to my fund-raiser and sponsored a table.”
Correction: April 5, 2018
An earlier version of this article misstated the given name of a state senator. He is Jeff Van Drew, not Chris.
On – 05 Apr, 2018 By NICK CORASANITI