President Donald Trump's second-term agenda faces an early test with voters Tuesday in New Jersey, a blue state holding the first statewide elections since Trump won back the White House last year.Trump isn't on the ballot in New Jersey's Republican gubernatorial primary this week. But the closely-watched GOP and Democratic primary races — along with statewide primaries in Virginia later this month — are widely seen as a referendum on the president's handling of the economy, immigration and other key issues in his first months in office."Trump looms large over this entire race on both sides of the aisle," said Ashley Koning, the director of the Eagleton Center for Public Interest Polling at Rutgers University-New Brunswick.Trump's EndorsementThe race to replace term-limited Democratic Gov. Phil Murphy has drawn special interest from Trump, who owns several properties in New Jersey and frequently spends weekends away from the White House at his golf club in Bedminster.Last month Trump endorsed Republican Jack Ciattarelli, a former state lawmaker and onetime Trump critic-turned-supporter who narrowly lost the 2021 governor's race to Murphy.The endorsement helped cement Ciattarelli's frontrunner status in a Republican primary field where all but one of the candidates are Trump backers. Whoever wins the GOP primary race will have history on their side: New Jersey voters have never backed the same party in three consecutive gubernatorial races.Trump has also been outspoken about his desire to flip New Jersey from blue to red. The state has voted for a Democratic presidential candidate in every election since 1988. Trump fell short in New Jersey in 2024, but he only lost the state by 5.9 percentage points, the best showing by a Republican presidential nominee in two decades. In 2020, Joe Biden carried the Garden State by 16 points.In backing Ciattarelli, Trump argued that New Jersey was ready for Republican leadership after Murphy's eight-year reign in the governor's mansion. Trump has long urged voters in blue states to change course and back himself and other MAGA-aligned Republicans."New Jersey is ready to pop out of that blue horror show and really get in there and vote for somebody that's going to make things happen," Trump said during a virtual rally for Ciattarelli held May 2.Republicans said Trump's endorsement would make a difference in the race."We believe his endorsement means a whole lot," Kennith Gonzalez, the executive director of the New Jersey Republican Party, said in an interview. Trump's second-term "agenda is very popular here in New Jersey."A late April survey conducted by the Eagleton Center for Public Interest Polling found that 46 percent of Republicans and Republican-leaning independent voters were more likely to back a candidate endorsed by Trump. Another 46 percent said Trump's endorsement would have no effect on their vote. Just 7 percent said his endorsement of a candidate would make them less likely to vote for that person.A Crowded Democratic FieldOn the Democratic side, Rep. Mikie Sherrill has held a slight polling lead in a crowded primary field that includes Rep. Josh Gottheimer, Newark Mayor Ras Baraka, Jersey City Mayor Steven Fulop and former state Senate President Steve Sweeney. Primary voters in New Jersey are also voting for state Assembly seats Tuesday. The Democratic candidates have spent the campaign attacking Trump more than each other. The strategy may work in the primary, but Democratic strategists said voters in the general election in November will be eager to hear more policy solutions on issues of perennial importance in New Jersey, such as rising property taxes crime and affordable housing."For Democrats, opposing Trump is the floor not the ceiling. Voters are looking for what else [candidates] are going to do past that," said Dan Bryan, a Democratic strategist and former senior adviser to Murphy.Because the New Jersey and Virginia gubernatorial races are the only statewide elections in the country in the off-year after a presidential election, they traditionally serve as an early bellwether for a new or re-elected president's popularity.The primaries in New Jersey aren't a perfect indicator of how a president and his party perform in the next midterm and presidential elections.Murphy beat Ciattarelli by three points in the 2021 race, and Democrats followed by outperforming expectations around the country in the 2022 midterms.But Trump carried all seven battleground states in his 2024 win over former Vice President Kamala Harris, and also did better than expected in some blue states like New York and New Jersey. Trump narrowed the gap in New Jersey with an uptick in support from Hispanic voters and other groups that historically back Democrats.Republicans said it was too early to predict whether the party has a realistic chance to carry New Jersey in the 2028 presidential election. But the state's political firmament is now ripe for a Republican to win the governor's mansion, party strategists and others said."The environment has gotten considerably better for Republicans" in New Jersey, said Adam Geller, the Ciattarelli campaign's pollster and a former Trump campaign pollster. "This is a state that's in play."