National Hispanic Heritage Month kicks off Sunday with Vice President Harris launching what NBC News describes as her “largest effort yet to reach Latino voters.” President Trump is enjoying historic support from the voting bloc, putting the Democrat on notice that she cannot take its support for granted.

The NPR/PBS News/Marist National poll released last week found Trump leading Ms. Harris 51 to 47 percent among Hispanics. That’s a nine-point swing from last month, and 16 points higher than the 35 percent of the now 36.2 million-strong group he earned in 2020. It’s also a 23-point improvement on his 2016 total.

CBS News conducted a poll last month after Mr. Biden dropped out of the race. The survey found that the swap for Ms. Harris was “not convincing Hispanic voters” with her “barely five points ahead” of Trump, “the smallest margin for a Democratic candidate so far this century.”

Last week, a UnidosUS poll found Ms. Harris’s support at 59 percent, below that of any Democrat to win the presidency over the last 40 years. It’s close to the 61 percent Mr. Biden won in 2020, but the momentum is trending for Trump.

The development seems to have caught the Harris campaign by surprise. It defies the conventional wisdom that Trump’s signature issue, illegal immigration, would doom him with the nation’s largest bloc of minority voters. Instead, the former president’s economic and border security messages are keeping him competitive.

The vice president of the UnidosUS Latino Vote Initiative, Clarissa Martínez De Castro, said in a statement accompanying the poll that “the rising cost of living, wages, and housing costs continue to be top of mind for Latino voters.”  Inflation, jobs, the economy, and housing were the top issues for those surveyed.

On immigration, Ms. Martínez noted that “Latino voters know the difference between those who mean us harm and those who are contributing to the fabric of our nation.” She said they want a candidate who’ll deliver both “relief for the long-residing undocumented population” and a crackdown on “human smugglers and drug traffickers.”

The president of BSP Research, Gary Segura, wrote alongside Ms. Martínez that Republicans “are held in generally lower regard” than Democrats “and garner trust only on issues of inflation and border.” But “both parties,” he said, “clearly have work to do to attract a larger share of this fast-growing electorate.”

Complicating analysis of what Hispanic voters want, UnidosUS found that “23 percent of Latino voters are eligible to vote for president for the first time” this year and 37 percent have gained the franchise since Trump’s first election. Being new to casting a ballot may mean they’re hungry to participate, and candidates will have to fill that need.

However, Ms. Martínez said that UnidosUs found “only 23 percent of Latino voters say they have heard from Democrats and 16 percent from Republicans.” This represents an opportunity to fill in the blanks, one Ms. Harris is seeking to meet with a blitz of ads on Spanish-language radio starting Sunday.

A senior Harris campaign official, NBC News reported, called the $3 million buy “among the largest and ‘most significant’ spending in Hispanic media ever.” It will target programs covering baseball, football, boxing, and soccer in areas the vice president needs to win.

Ms. Harris will also address the Congressional Hispanic Caucus Institute’s annual conference on Wednesday. Meanwhile, NBC News reports that her running mate, Governor Walz, “is expected to pitch Latino voters in swing states in the coming weeks” as will other surrogates.

Early voting will begin soon in battleground states with large Latino populations. These include Arizona, where a quarter of voters are Hispanic, and Nevada, where one-in-five is. In Pennsylvania, which Mr. Biden won by just 80,000 votes, they make up six percent of those eligible.

Hispanics are a diverse voting group reflective of the broader American electorate. They’re putting the candidates on notice that their support must be earned not assumed. How well Trump and Ms. Harris pitch without pandering will decide if this Hispanic Heritage Month goes down as the one that picks a president.