WASHINGTON — Joe Biden has long counted on his vast popularity among African American voters as crucial to his 2020 presidential campaign's success. But Hispanics, the nation’s fastest growing minority group, aren’t quite yet sold on the former vice president.

Efforts to court Hispanic voters come at a critical juncture: The 2020 election will be the first in which Hispanics make up the largest racial or ethnic minority in the electorate, according to the Pew Research Center. While Hispanics largely vote Democratic and polls show a majority disapprove of President Donald Trump's tenure, no individual Democratic candidate can yet claim a hold on the diverse Hispanic community.

Critics say the Biden campaign has missed opportunities to reach out to Hispanic voters early on, allowing rivals to make inroads and build support.

"People need to have the opportunity to see and hear from the candidate. and I think he hasn’t done enough on outreach," Christine Newman Ortiz, Director of Voces de La Frontera, a Wisconsin-based Hispanic advocacy group, said of Biden. Showing up, she adds, is “a sign of respect” to the community.

Arturo Vargas of the National Association of Latino Elected Officials (NALEO) echoed that point. In an interview with NBC News, Vargas said Biden’s name recognition among Hispanic voters gives him a huge advantage in the large 2020 Democratic field. But if he doesn’t step up his visibility, Vargas said, Biden is "giving an opening to other Democratic candidates."

Biden's campaign insists it is ramping up its outreach efforts and hoping that that increased support among Hispanics could improve the former vice president's odds. One Biden campaign official involved with outreach told NBC News that Biden is expected to soon engage with more Latino communities across the country from East Los Angeles to Des Moines, Iowa, to stress his message of inclusion. Staffers and several of Biden’s 32 Hispanic endorsers will devote more time to meet with prospective supporters and share his message, which highlights how Latinos have contributed to society and how a Biden presidency would help them regain stable economic footing and cultural recognition.

"From the very first day, before the campaign launched, there was a very strong commitment from Vice President Biden to take seriously the Latino community and Latino voters," Biden senior campaign adviser Cristobal Alex told NBC News.

But other Democratic candidates have already outpaced Biden on Latino outreach by holding numerous Hispanic-focused town halls, meetings and rallying events.

O’Rourke, a fluent Spanish speaker, has held 10 Hispanic-focused events across the country. He was also the only Democratic candidate to visit Mississippi days after the Trump administration carried out its largest immigration raids there this year.

Former Housing Secretary Julián Castro is the sole Latino candidate in the Democratic field and his identity plays a large part in his campaign events and outreach. Castro, who is Mexican American, began his campaign in Puerto Rico and regularly visits Hispanic communities across the country.

Nevertheless, Biden continues to be a top choice for Hispanics. In a Univision poll released this month, Biden was essentially tied with rival Bernie Sanders among Hispanic voters, 22-20 percent. Castro placed third with 12 percent.

Univision pollsters said Biden and Sanders' positions in the poll mainly reflect both men’s high name recognition among Hispanic voters. Support could shift, the pollsters said, as Hispanics become familiar with other candidates.

Biden, for his part, has taken a largely traditional approach to wooing Hispanics, starting with outreach to key community leaders. He was the first candidate to request a meeting with the BOLD Pac, the Congressional Hispanic Caucus’ fundraising arm, and he’s held roundtables with prominent Latino community leaders in San Diego and Las Vegas.

Biden, along with several other Democratic contenders, attended a presidential forum this summer hosted by the Hispanic civil rights group UNIDOS US. But he notably skipped similar forums hosted by the League of United Latin American Citizens (LULAC) and NALEO due to conflicts with his campaign schedule, drawing criticism from activists.

“I think it was a missed opportunity, and it was a disappointment for many there,” Vargas said.

Joe Biden speaks at the UnidosUS Annual Conference's Luncheon in San Diego on Aug. 5, 2019.

Biden’s first meet and greet with members of the Hispanic community came in mid-September in Little Havana, Miami, where roughly 300 Democratic and Republican voters packed into the historic Ball & Chain salsa club to hear him make his pitch.

Jay Varano, 26, from Fort Lauderdale, voted for President Trump in 2016, but is now “all for Biden.”

“I consider the president to be the No. 1 diplomat for the United States, a symbol for America, and I don’t think Trump’s doing a good job with that,” he said. “I think Joe Biden has the foreign policy experience and he has all the connections to do what’s right in the White House.”

Victor Monzon-Aguriie, a Miami native and lifelong Republican who does not support Trump, told NBC News he is a fan of Biden’s but needed to "look him in the eye" and hear from him directly. Pete Buttigieg, the South Bend, Indiana, mayor, is his second choice.

NBC News spoke to half a dozen Democrats at the Miami event, and like Monzon-Aguiire, they admired Biden, but were not sold on supporting him until they heard his message.

"Joe has been around the block, but I’m hesitant with Joe,” he said, suggesting that his time in politics has passed. “I need to hear his voice and his sincerity. I just want to hear what he says.”

Biden's campaign has tapped his Hispanic endorsers and campaign surrogates like Nevada State Senator Yvanna Cancela to help sell his message.

Other outreach efforts have begun in Nevada, the first early voting state with a large number of Hispanic voters. The campaign there has been holding bilingual phone banks, while also building relationships with Hispanic-owned businesses throughout the state. They see their potential successes in Nevada as a template for groundwork in states like California and Florida, both of which hold primaries weeks later.

Volunteers speaking with undecided Hispanic voters are suggested to highlight Biden as a family man according to three Biden campaign officials. They also stress Biden’s experience in passing bipartisan legislation and his record on pursuing health care, economic and immigration reform, the top three issues cited as most important to Latinos in numerous polls.

Those selling points are ones that Yesenia Martinez, who volunteers for the campaign, tells her friends when they ask her why she is enthusiastically supporting Biden.

“He has the experience, he has seen many changes and has also been a part of getting America back on track,” Martinez, 29, said.

In his Miami appearance, Biden described how, as vice president, he helped the Obama administration broker a deal with three so-called Northern Triangle countries— Guatemala, Honduras and El Salvador— that helped curb illegal immigration. He also endorsed giving citizenship to Dreamers, undocumented immigrants who arrived in the U.S. as children.

But Biden's ties to the Obama administration, which oversaw the deportation of millions of undocumented immigrants, have also emerged as a pain point for some activists. Pro-immigration protesters interrupted the former vice president during both the July and September Democratic debates. Similar demonstrations also upended one of Biden's New Hampshire events in July and his Philadelphia campaign office.

Alfredo Calderon, a 21-year-old Mexican-American working in Las Vegas as a housekeeper, said he told Biden at a campaign stop that his father had been deported during the Obama years despite having no criminal record.

Calderon, who was already supporting Biden, said that the former vice president promised to bring Calderon’s father back to the United States. Biden’s sincerity and attentiveness, Calderon said, made him believe Biden would keep his promise and end family separations.

"At the end of the day you can say President Barack Obama was Joe Biden’s boss," Calderon said. "At the end of the day he has his own vision, which I like, and it’s different than President Obama’s."

Claudia Martinez of UNIDOS US said that candidates should not just pitch immigration reform to Hispanic voters because “they’re not a single issue constituency.” However, she urged the Biden campaign to provide more specifics about his immigration reform plans. The Biden campaign promised to release a fuller immigration reform plan soon.

But some Hispanic voters are looking beyond the policy prescriptions proposed by the candidates, instead focusing on who is delivering that message. Most of the younger Hispanic voters that NBC News interviewed are more interested in hearing from candidates of color in the Democratic field rather than those with experience.

"He’s a white male and I’m a Latina, so I think we’re very far apart from who we are and he will never understand," Laura Castro, 32, said of Biden.

Even though Biden’s strong status in the polls has been slipping, many voters still see him as their best shot to beat Trump.

Alexandra, a middle-age woman from Miami who declined to give NBC News her last name in fear of retaliation from her job, said she "loves" Buttigieg, but said that the election should be "about voting for who has the best chance to beat the president. I think that’s Biden."

After hearing Biden outline why he’s running for president and how he plans on uniting all Americans, including the Hispanic community, Monzon-Aguriie was moved. He did not say if Biden fully won his support that day, but his voice quivered when discussing the message that resonated with him the most.

“He told us who we are. He reminded us who we are. That’s important. People forget it.”