Sen. Cory Booker, D-N.J., is getting advice from one of former President Barack Obama's campaign leaders in New Hampshire as he considers a run for the White House in 2020, CNBC has learned.

Jim Demers, a co-chairman of Obama's New Hampshire campaign organization in 2008, is becoming known as Booker's "tour guide" within the state.

"I have told Cory if he runs, I plan to support him," Demers said in an email to CNBC. He noted that he assisted Booker during his trip to New Hampshire a couple of weeks ago and plans to do the same in December when Booker attends the New Hampshire Democratic Party's midterm victory celebration.

"I have introduced him to multiple elected officials in N.H.," Demers added.

Booker's engagement with top political operatives in New Hampshire, a state that holds one of the earliest contests of the presidential election season, shows he is surrounding himself with people who could help him mount a formidable campaign for the Democratic nomination.

The development also comes after CNBC learned that Booker was developing relationships with top-tier campaign strategists in Iowa, which holds its stage-setting caucuses earlier than New Hampshire's primary.

Demers expressed his support for a Booker run early on. "I have been watching this guy for several years now. He has got, I think, that 'it' factor," the New Hampshire political operative told The Washington Times in February. He did not say at the time that he would become one of Booker's top advisors.

A spokesman for Booker declined to comment.

Kathy Sullivan, a former chairwoman of the New Hampshire Democratic Party, is one of the influential people Booker met through Demers. Sullivan was a staunch supporter of Hillary Clinton during the 2016 presidential election.

"My husband and I had dinner with Senator Booker and a few other people just before the midterms when he was in New Hampshire," Sullivan told CNBC. "Jim Demers was really the one acting as a tour guide."

The conversation focused on the midterms, but it also turned into what Sullivan described as a "getting-to-know-you meeting."

The New Hampshire primary is one of the early hurdles for any presidential candidate, although it isn't always a must-win. Obama lost the state's 2008 primary to Hillary Clinton by just under 3 percentage points.

Clinton fell in the same primary in 2016 when she was in a surprisingly tough race for the nomination against Sen. Bernie Sanders, I-Vt. Sanders trounced Clinton by over 20 points, but she went on to capture the Democratic Party nomination that year. Then-candidate Donald Trump won the state's Republican primary and later defeated Clinton in the general election.