CONCORD, N.H. (AP) — Before he cut the $100,000 checks, Los Angeles Mayor Eric Garcetti brought the Democratic Party chairmen from Iowa, New Hampshire, South Carolina and Nevada backstage to meet late night television host Jimmy Kimmel and superstar hip-hop producer DJ Khaled.

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Garcetti may not be the best-known 2020 presidential prospect, but he will not be forgotten by those who lead Democratic politics in the states most responsible for picking the party's next presidential nominee.

After the star-studded California fundraiser late last month that featured 10 state-party chairmen, followed by a private dinner, Garcetti issued $100,000 checks to each of their state parties. It was the money, more than the celebrity, that impressed New Hampshire Democratic Party Chairman Ray Buckley.

"Obviously, to those who are helpful, we are extraordinarily grateful," Buckley told The Associated Press. "So many of our states are battling epic elections."

Many of the Democratic Party's most ambitious have begun building relationships on the ground in the states most responsible for picking the next presidential nominee, although few are doing it as brazenly as the Los Angeles mayor. Most are more quietly endearing themselves to local candidates with phone calls, emails and donations up and down the ballot across Iowa, New Hampshire, South Carolina and Nevada, the states expected to host the first four presidential primary contests in roughly 15 months.

The early-state relationships require a delicate balance for those who want to stand out in a crowded field next year without neglecting the high-stakes midterm elections this fall. Control of Congress and state houses across the nation is up for grabs in just three weeks.

Sen. Cory Booker of New Jersey has raised more than $7 million and campaigned across 21 states for other Democratic candidates this midterm season, according to an aide. He also attended a family reunion with extended relatives in Iowa last week before and after stumping for dozens of down-ballot candidates for offices like secretary of agriculture and state auditor.

Booker, who is openly contemplating a 2020 bid, campaigns for South Carolina Democrats on Thursday.

WASHINGTON, DC - JULY 24: Sen. Cory Booker (D-NJ) and Sen. Elizabeth Warren (D-MA) attends a press conference on July 24, 2018 in Washington, DC. The group of moral leaders spoke to highlight the danger Judge Brett Kavanaugh's Supreme Court nomination poses to the rights of historically marginalized communities. (Photo by Tasos Katopodis/Getty Images)

Sen. Elizabeth Warren of Massachusetts is in the midst of her own re-election campaign, as well as a midterm blitz to help other Democrats nationwide win their races. While she has not yet campaigned for Democrats in neighboring New Hampshire, she was among the first elected officials to call gubernatorial candidate Molly Kelly on the night of her primary election victory.

Warren has also designated staff to help candidates in the early states, including former staffers now working for state parties in New Hampshire and South Carolina.

CAMBRIDGE, MA - SEPTEMBER 09: U.S. Sen. Elizabeth Warren speaks at a rally held for Democratic gubernatorial candidate Jay Gonzalez (L) and congressional Democratic candidate Ayanna Pressley (2nd L) on September 9, 2018 in Cambridge, Massachusetts. (Photo by Scott Eisen/Getty Images)

In Iowa, congressional candidates J.D. Scholten and Cindy Axne got a campaign boost from former Housing Secretary Julian Castro last weekend; Sen. Bernie Sanders of Vermont is expected to rally supporters behind Scholten later this month.

Iowa Democrat Deidre DeJear, the party's nominee for secretary of state, has attracted support from several presidential prospects, none more helpful than California Sen. Kamala Harris. They met in Los Angeles at an April event sponsored by The Links, a service organization dedicated to black professional women.

Their bond has grown since.

On the day of her June primary, DeJear got a phone call of encouragement from Harris before narrowly winning her race, becoming Iowa's first black nominee for statewide office from a major political party. The California senator attended a fundraiser for DeJear in Washington and later this month plans to make her first trip to Iowa to rally young voters on DeJear's behalf.

"Having big names in Iowa really can drive people to early vote, drive people to volunteer — it's just an extra level of excitement," said Cynthia Sebian-Lander, DeJear's campaign manager. "What we need to do is use these visits as a way to talk about our down-ballot candidates and the importance of voting in every single race."

Beyond Iowa, Harris has raised more than $1 million over the first 15 days of October to help Democratic candidates, according to an aide. She has traveled to 10 states and plans to travel to South Carolina late this week.

Sen. Kirsten Gillibrand of New York, who has spent much of the year working to help elect female candidates across the country, has sent out nine emails to raise money for Nevada Senate candidate Jacky Rosen. Gillibrand took 20 minutes during the recent Supreme Court debate to address Nevada Democrats, via teleconference.

WASHINGTON, DC - SEPTEMBER 28: U.S. Sen. Kirsten Gillibrand (D-NY) (L) speaks as Sen. Kamala Harris (D-CA) (R) listens during a rally in front of the U.S. Supreme Court September 28, 2018 in Washington, DC. Activists staged a rally to call to drop the nomination of Judge Brett Kavanaugh to the U.S. Supreme Court. (Photo by Alex Wong/Getty Images)

"What you're doing in this campaign could flip the Senate," the New York Democrat said in a video projected on the wall. "I think that Jacky's seat is one of the most important, if not the most important seat."

While it may seem early, political veterans note that off-year elections can be critical in the multistage process of running for president. While President Donald Trump ignored laying such groundwork and found success, relationships in the early states are expected to matter — particularly in a field that could attract as many as two dozen candidates.

In addition to the young senators, the early prospects range from former Vice President Joe Biden to attorney Michael Avenatti to Washington Gov. Jay Inslee to South Bend, Indiana, Mayor Pete Buttigieg.

Garcetti is using his southern California connections to try to separate himself from the pack.

Already a frequent visitor to early voting states, he got the idea for a glitzy Los Angeles event after raising $100,000 for the South Carolina Democratic Party. Garcetti ultimately helped raise $1.5 million at the late-September fundraiser in Los Angeles with Kimmel and Khaled that also attracted top California moneymen such as LinkedIn co-founder Reid Hoffman, sports and entertainment executive Casey Wasserman and former Disney Chairman and CEO Michael Eisner.

Ten state parties received $100,000 checks, a group that included the early states and Midwestern battlegrounds like Michigan, Minnesota, Ohio, Pennsylvania and Wisconsin.

Former South Carolina Democratic Party chairman Jaime Harrison said he's encouraged to see the energy surrounding the early-state action.

"I think this going to be a free for all," he said.