Four years ago, East Las Vegas, Nev., was a hub for presidential candidates engaging in heavy retail politicking. This year, it was anything but.

In 2020, Democrats came to the state months before its first-in-the-West presidential caucuses: Joe Biden, then a former vice president, took selfies at a well-known taco spot; Senator Bernie Sanders of Vermont held an “Unidos con Bernie” soccer tournament; and four candidates picketed alongside a powerful union dominated by Latinas.

But as the 2024 contests approached, and a number of Republicans lined up to challenge former President Donald J. Trump, things were visibly different. No campaign signs lined the area’s strip malls. There were no Republican presidential candidate ads on the air. With attention on the Super Bowl, taking place in the city this weekend, many Latino voters in Clark County were unaware of the contests of the political sort that were also taking place this week.

The reason: Nevada’s Republican Party split the nominating contests in two, rendering a state-run primary on Tuesday meaningless and conducting a separate caucus on Thursday where Mr. Trump is running essentially unopposed. As a result, the candidates largely ignored the state — and, many Latino organizers argued, Republicans on the whole missed out on an opportunity to reach a key voting group early.

Nearly a dozen community leaders said the complicated dual contest had also caused confusion among many Latinos, which could dissuade potential new voters from participating and make it less likely that they will come back in the fall.

“Voters, especially Latino and Hispanic voters, are paying real attention right now, more than they ever have — so that means they’re paying attention to the fact that they were ignored,” said Peter Guzman, the president of the Latin Chamber of Commerce, Nevada, who identifies as a moderate conservative.

“I want them to be present and intentional,” he said of Republican candidates, “and I think that ignoring our state, ignoring a big segment of the voters, is a big mistake.” Changes to the primary process, he added, caused “a lot of confusion in the Hispanic community.”

Nevada is the first early voting state where Latino voters make up a large share of the electorate, comprising 20 percent of voters. That constituency has been heavily courted by presidential candidates of both parties in the last several elections, a testament to the group’s growing power as Nevada has become a contested battleground where slight shifts can determine the winner of a close race.

One only has to look to the recent past for evidence of why starting early in Nevada can matter: In 2020, candidates flocked to the state ahead of the competitive primary, during which many made reaching Latino voters a priority. That initial outlay helped power the party’s efforts the rest of that year, ultimately aiding Mr. Biden in the general election with support from Latino voters.

Democrats competing in Nevada have historically drawn more support among Latino voters, built on years of organization and alignment on issues like immigration policy. But Republican efforts to reach them increased in 2016, during the competitive presidential primaries, when candidates like Mr. Trump and Senator Marco Rubio of Florida met with community leaders and sent out frequent mailers.

And recent polls have shown that Democrats could be losing ground with a number of Latino voters — some disillusioned with their economic prospects or a lack of action on immigration, others looking for a strong stance against what they perceive as communism.

Maria Salazar, who leads Latino outreach for the super PAC supporting Nevada’s Republican governor, Joseph Lombardo, said the state’s rapidly-growing Latino population means the two parties are in “a race, more than ever, to reach as many Latino voters as possible.” But she described the Republican nominating contests as “confusing” for some, and said it’s been a “learning process” for new Republican voters unfamiliar with the system.

Communication between this year’s Republican slate of candidates and Latino voters has been scarce.

Though Mr. Trump, the Republican front-runner, has appeared in Nevada a handful of times, the number of trips pales in comparison to his activity in other early contest states. His remaining rival, Nikki Haley, the former governor of South Carolina, has not “spent a dime nor an ounce of energy on Nevada,” according to her campaign — and faced a devastating second-place finish behind the “none of these candidates” option in Tuesday’s primary, which Mr. Trump did not participate in. He’ll compete in Thursday’s caucuses, where Ms. Haley is not on the ballot.

Many of the other candidates who previously dropped out also had rarely set foot in the Silver State, a shift from 2020, when some candidates trekked out a year in advance. And neither Mr. Trump nor Ms. Haley had made ad buys in the final months before Nevada’s contests, according to data from AdImpact, a media tracking firm.

The minimal investment may have contributed to a lack of awareness among voters on Tuesday, when the first primary contests took place. Voters were sparse across several polls in Latino-dominated parts of Clark County in the final hours before polls closed. When a Times reporter spoke with more than a dozen visitors to a Hispanic grocery store in East Las Vegas, the majority said they had not known a contest was happening. Only one said that he had participated in the primary — Jose Alonso, 66, who voted for Mr. Biden.

Mr. Trump’s allies have pointed to his improved support among Nevada Latinos during his last campaign, as well as his dominant front-runner status in the G.O.P. primary campaign, as proof that his relative absence from the state would not affect his success in the fall. He won 37 percent of the Latino vote in Nevada in 2020, up eight percentage points from the 29 percent he received in 2016.

“He’s already addressing general campaign issues — he’s already in general mode with Nevada,” said Jesus Marquez, a political consultant and a Trump surrogate.

Mr. Marquez, who has for years helped lead Latino outreach efforts for Mr. Trump and other Republicans in Nevada, said he had instead focused on outreach at churches in the state over the last few months.

In the absence of presidential candidates communicating Republican pitches to Latino voters, a handful of groups have stepped in. Americans for Prosperity, the group founded by the conservative industrialists Charles and David Koch, and the Libre Initiative, an affiliated wing that reaches Latinos, have worked in Nevada to negatively portray the Biden administration’s economic approach as Nevada has faced high prices and unemployment rates.

“Anytime we fail to engage constituents that are feeling the effects directly — more so than perhaps any other demographic — is a huge missed opportunity to connect,” said Ronald Najarro, A.F.P.’s Nevada director. Underscoring that sentiment, the Libre Initative on Wednesday released a seven-page memo to both parties that stated that Republicans, to reach Latino voters, “must increase tactical investments, earlier and more often.”

Eddie Diaz, the Nevada strategic director for the Libre Initiative, said the group was focused on campaigning for Sam Brown, one of the Nevada candidates vying to challenge Senator Jacky Rosen. His group has heard from moderate Latino voters who do not want a rematch between Mr. Biden and Mr. Trump, and he posited that a new Senate candidate could perhaps drive those voters to the polls.

Latino groups allied with Democratic causes say the confusion Republicans caused among their voters was just the latest sign of dysfunction. They have used the absence of activity to ready their own operations to educate voters and have pushed back on suggestions that Latinos are supporting Republicans in droves while echoing the sentiment of the Biden administration: that Mr. Trump’s comments on immigrants would push Latinos away.

“That rhetoric turns them off and makes it so that you cannot trust the person that’s delivering the message,” said Manuel Santamaria, the Nevada state director for Mi Familia Vota, a national Latino voting group.

Some of the groups, however, argued that voters get short shrift. Lack of engagement from national Republicans, several said, neglects a truth about Nevada’s electorate: that it is constantly shifting, meaning that candidates every cycle need to prepare to engage constituencies who might not have previously been there.

“The shortsightedness the Democratic and Republican parties face by not investing early for the primary and caucus contests is that a lack of excitement is contagious,” said Leo Murrieta, director of Make the Road Nevada, a liberal advocacy group that focuses on Latinos. “It will make it that much harder to engage people as we get closer to the general election and explain to them that their vote matters, that they have a role to play in shaping our democracy.”