U.S. Rep. Donald Norcross swept to an easy victory Tuesday to win the First Congressional District Democratic primary in New Jersey.

In his first reelection bid, Norcross beat back a challenge by Alex Law, who was running for office for the first time.

In unofficial returns, Norcross won with 70 percent of the vote. He emerged from an unexpectedly hotly contested and expensive House race to represent the heavily Democratic district, which covers parts of Camden and Gloucester Counties as well as Maple Shade and Palmyra in Burlington County.

In November, Norcross will face GOP challenger Bob Patterson of Haddonfield, who was unopposed in the Republican primary.

At the Camden County Democratic Committee headquarters in Cherry Hill, about 100 people awaited results in a festive room decorated with patriotic colors.

"We have proof that if you come after one of us, you come after all of us," State Sen. James Beach, the county party chairman, told the cheering crowd.

Norcross thanked the crowd and his mother, who died during the campaign. He said he would continue to push for more jobs and safer neighborhoods.

"This is the American dream," Norcross said.

Norcross picked up an endorsement last week from President Obama in what should have been a relatively safe seat for the freshman lawmaker to retain.

Law, 25, ran an aggressive campaign, taking aim at the Norcross family name and the powerful Democratic political machine. Donald Norcross is the brother of South Jersey political leader George E. Norcross III.

At his headquarters in Haddon Township, Law tearfully conceded in front of about 60 supporters. He said he was proud of his campaign, which was outspent and outmanned.

"We made a lot of history," Law said. "We we did something that no other campaign has been able to do in South Jersey."

The crowd, made up largely of high school and college students who worked on the campaign, stayed stoic as the results came in.

"We almost cried - we started to cry, but then decided to stay strong for Alex," said Kim Tang, 18, a senior at Eastern Regional High School in Voorhees. "But he's 25. He's going to be able to do great things."

The Law campaign stumbled last week after the Gloucester County NAACP chapter canceled a debate between Law and Norcross, citing a dispute over logistics with Law, while Law accused the head of the civil rights organization of bias.

A former International Business Machines Corp. consultant, Law put together an upstart campaign that went door to door. He raised about $40,000, compared with Norcross' nearly $1 million.

Despite the heated rhetoric, attacks, and a flurry of campaign fliers, the race fizzled quickly Tuesday. The first inkling of the outcome came when preliminary results showed Norcross handily leading Law in mail voting in Camden County by 3-1.

Law left open the possibility of another campaign. "I don't think I'll leave politics completely, whether that's commenting on things, running for things, helping other people," he said.

During the campaign, Law, of Voorhees, called for raising the minimum wage, decriminalizing marijuana, and making college more affordable. He criticized Norcross' voting record on high-profile issues such as the Iran nuclear deal and approving the Keystone pipeline agreement.

Darron Outler, 49, of Voorhees, a regional sales manager for a plant fertilizer company, said he voted for Norcross because he didn't know much about Law. Outler said that he was lukewarm on Norcross, but that Norcross was at least a "known evil."

Norcross was elected to the seat in 2014, replacing Rep. Robert E. Andrews, who resigned amid an ethics probe to join a Philadelphia law firm.

A former labor leader and electrician, Norcross, 57, was elected to the Assembly in November 2009. Two months later, he was appointed to the state Senate. He won a special election in 2010 and was later elected to two full terms.

mburney@phillynews.com

856-779-3814 @mlburney

Staff writers Emma Platoff and Erin Serpico contributed to this article.