New Jersey House Race Narrows in Final Days

For weeks, a congressional seat in one of the country’s most closely watched swing districts seemed destined to remain under Republican control.

America PAC, a political action committee founded by Elon Musk, the world’s richest man, has used digital ads to boost the Republican incumbent in the New Jersey race, Thomas Kean Jr. Another PAC, the Republican Congressional Leadership Fund, has flooded prime-time television with nearly $3 million in commercials that depict Mr. Kean’s Democratic challenger, Sue Altman, as a “radical liberal” who supported “decriminalizing crack, heroin and fentanyl.”

Yet with recent polls suggesting that the gap separating the candidates has narrowed, the Democrats have mounted a last-minute push.

On Tuesday, in an 11th-hour sign of confidence, the campaign arm of House Democrats who are fighting to win back a majority they lost two years ago made its first monetary contribution to Ms. Altman. The fund, the House Majority PAC, committed to spend about $4 million in the last two weeks of the race as it released its first TV ad on her behalf.

Supporters of Ms. Altman had publicly criticized the lack of financing from the national Democratic Party. And last week, after an independent poll showed that Mr. Kean was leading by just two percentage points, New Jersey’s governor, Philip D. Murphy, called Representative Hakeem Jeffries of New York, the House Democratic leader, to urge support by the House Majority PAC.

“This is an incredibly tight and closing race,” Mr. Murphy, a Democrat, said in an interview on Monday before the PAC announced its $4 million infusion of support. “It is quite clear that she’s got the momentum.”