Democrats need Latinos at the polls. But will they reveal themselves?

This can be hard work, but even in the era of digital advertising and explosive texts, prospecting is considered the norm par excellence in political organization. Face-to-face contact has been proven to increase a voter's chances of success. "The way you get it does not spend an extra $ 2 million on television ads," Jones said. "It's time to build an army on the ground."

In Nevada, and especially in Clark County, which includes Las Vegas, unions have become powerful engines to convince voters. Mrs. Henry said S.E.I.U. State members have already knocked on the door of 15,000 Hispanic and Asian voters, and the union took a few hundred of its Californian members to Nevada by bus to participate in mobilization activities on Saturday, the first day of early voting in the state. .

In Clark County, home to over three-quarters of the state's population, there may be no stronger political force than Local 226 of the Culinary Workers Union, known in the county as from Culinary. The 57,000-member union provides cooks and cleaners with many months of holiday time to focus on politics. The union put its weight behind Ms. Rosen.

Such a game book is, however, difficult to replicate in other states.

In the districts of the Central Valley of California, which are very agrarian, the Latinos "have not had much communication, especially at their door, from the Democrats – either because these districts have not been in operation since. some time, because unfortunately underfunded, "said Katie Merrill, chief strategist for Fight Back California, a Democratic group.

Hispanic voters could decide on the half dozen competitive races held in California, but their turnout remains an important point of questioning. To win these seats, Democrats "need more of these Latinos, those who do not vote often," said Merrill.

In the central valley district of David Valadao's representative, Mr. Valadao's Democratic rival, T.J. Cox, tried to make the race a referendum on Mr. Trump. Mr Valadao was reelected by 13 points, even though Mr Trump lost the district by more than 16 points.