MIAMI (AP) -- Having fled economic and political chaos in Venezuela, Luisana Silva now loads carpets for a South Carolina rug company. She earns enough to pay rent, buy groceries, gas up her car -- and send money home to her parents.

Reaching the United States was a harrowing ordeal. Silva, 25, her husband and their then-7-year-old daughter braved the jungles of Panama's Darien Gap, traveled the length of Mexico, crossed the Rio Grande and then themselves in to the U.S. Border Patrol in Brownsville, Texas. Seeking asylum, they received a work permit last year and found jobs in Rock Hill, South Carolina.

"My plan is to help my family that much need the money and to grow economically here," Silva said.

Her story amounts to far more than one family's arduous quest for a better life. The millions of jobs that Silva and other new immigrant arrivals have been filling in the United States appear to solve a riddle that has confounded economists for at least a year:

How has the economy managed to prosper, adding hundreds of thousands of jobs, month after month, at a time when the Federal Reserve has aggressively raised interest rates to fight inflation -- normally a recipe for a recession?

Increasingly, the answer appears to be immigrants. The influx of foreign-born adults vastly raised the supply of available workers after a U.S. labor shortage had left many companies unable to fill jobs.

More workers filling more jobs and spending more money has helped drive economic growth and create still-more job openings. The availability of immigrant workers eased the pressure on companies to sharply raise wages and to then pass on their higher labor costs via higher prices that feed inflation. Though U.S. inflation remains elevated, it has plummeted from its levels of two years ago.

"There's been something of a mystery -- how are we continuing to get such extraordinary strong job growth with inflation still continuing to come down?'' said Heidi Shierholz, president of the Economic Policy Institute. "The immigration numbers being higher than what we had thought -- that really does pretty much solve that puzzle.''

While helping fuel economic growth, immigrants also lie at the heart of an incendiary election-year debate over the control of the nation's Southern border. In his bid to return to the White House, Donald Trump has vowed to finish building a border wall and to launch the "largest domestic deportation operation in American history." Whether he or President Joe Biden wins the election could determine whether the influx of immigrants, and their key role in propelling the economy, will endure.

The immigration boom was a surprise. In 2019, the Congressional Budget Office had estimated that net immigration -- arrivals minus departures -- would equal about 1 million in 2023. The actual number, the CBO said in a January update, was 3.3 million.

Thousands of employers desperately needed the new arrivals. The number of native-born Americans in their prime working years -- ages 25 to 54 -- was dropping because so many of them had aged out of that category and were nearing or entering retirement. Their numbers have shrunk by 770,000 since February 2020, just before COVID-19 slammed the economy.

Filling the gap has been a wave of immigrants. Over the past four years, the number of prime-age workers who either have a job or are looking for one has surged by 2.8 million. And nearly all those newcomers -- 2.7 million, or 96% of them -- were born outside the United States.

At the Flood Brothers farm in Maine's "dairy capital'' of Clinton, foreign-born workers make up half the staff of nearly 50, feeding the cows, tending crops and helping collect the milk.

"We cannot do it without them," said Jenni Tilton-Flood, a partner in the operation.

For every unemployed person in Maine, after all, there are two job openings, on average.

A study by Wendy Edelberg and Tara Watson of the Brookings Institution found that new immigrants raised the economy's supply of workers and allowed the United States to generate jobs without overheating and accelerating inflation.

In the past, economists typically estimated that America's employers could add no more than 60,000 to 100,000 jobs a month without overheating the economy and igniting inflation. But when Edelberg and Watson included the immigration surge in their calculations, they found that monthly job growth could be roughly twice as high this year -- 160,000 to 200,000 -- without exerting upward pressure on inflation.

Trump has repeatedly attacked Biden's immigration policy over the surge in migrants at the Southern border. Only about 27% of the 3.3 million foreigners who entered the United States last year did so through as "lawful permanent residents'' or on temporary visas, according to Edelberg and Watson's analysis. The rest -- 2.4 million -- either came illegally, overstayed their visas, are awaiting immigration court proceedings or are on a parole program that lets them stay temporarily in the country.

"So there you have it,'' Douglas Holtz-Eakin, president of the conservative American Action Forum, said. "The way to solve an inflation crisis is to endure an immigration crisis."

Many economists suggest that immigrants benefit the U.S. economy. They take low-paying but essential jobs that most U.S.-born Americans won't, like caring for the sick and the elderly. And they can make the country more innovative because they are more likely to start businesses and obtain patents.

Critics counter that a surge in immigration can force down pay, particularly for low-income workers. Last month, in the most recent economic report of the president, Biden's advisers acknowledged that "immigration may place downward pressure on the wages of some low-paid workers" but added that most studies show that the impact on the wages of the U.S.-born is "small."

Holtz-Eakin argued that an immigration cutoff of the kind Trump has vowed to impose, if elected, would result in "much, much slower labor force growth and a return to the sharp tradeoff'' between containing inflation and maintaining economic growth that the United States has so far managed to avoid.

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Wiseman and Rugaber reported from Washington, Salomon from Miami.