It's a midweek evening in a northern suburb of Las Vegas, and all but one of the street-facing shops and offices on the block are closed for the night.

From the only office with lights on comes the crackle of a sound system, booming out Sinatra ballads that just about drown out the chatter and laughter of the heaving crowd inside. Seated around five long tables are dozens of first- and second-generation Asian immigrants, patiently waiting for the speeches and songs to end so they can feast on a specially-prepared Filipino meal.

If Hillary Clinton wins Nevada, her victory will be rooted in scenes such as this. The setting, one of 17 field offices run by her campaign in this battleground state, is the heart of a sophisticated ground game that has been years in the making.

The theme of this evening's dinner, "Filipinos for Hillary", has drawn some of the campaign's most active volunteers from one of the fastest-growing minority groups Las Vegas. "We don't just go and show up at community events. We try to create spaces where people can meet," says Philip Kim, a young and enthusiastic party activist who works for the Clinton campaign in Nevada as outreach director for Asian and Pacific-Islander communities.

Around the tables are some of the volunteers who, for the past 18 months, when the field offices opened, have been knocking on doors, distributing leaflets and manning phone banks. Their work is chronicled in the photos that line the walls, surrounded by hand-written slogans for canvassers to operate by (“Engage with a purpose”) or to emphasise to undecideds (“Revive the middle class”).

Now these volunteers are approaching the endgame. With just days to go before early voting begins on Saturday, they will be charged with getting friends, families and Clinton-supporting neighbours from their community to the ballot boxes.

Immigration reform

Kim, a veteran of Barack Obama’s re-election campaign in Florida in 2012, is nervous but plainly excited at seeing plans fall into place. “What makes this operation particularly good is that we have a lot of targeted data,” he says. “This is cool,” he adds, nodding towards the crowd. “Very, very cool.”

As the meal is about to begin, the room goes quiet, the lights dim and the organisers play a specially-produced video interview in which Clinton speaks about her work with the Filipino community. She reiterates her backing for comprehensive immigration reform and says she would act to speed up family reunification.

She also declares support for the Philippines in its dispute with China over territory and sovereignty in the South China Sea, prompting loud applause from the room.

Nevada is home to about 220,000 Asian-Americans and Pacific Islanders, most of them Filipinos based in Clark County, which comprises Las Vegas and its hinterland. The community is growing faster than the Hispanics, and winning them over has been a plank of Clinton's grassroots campaign in the state.

Clinton's own links with Filipino-Americans go back to her husband's time in the White House, says Rozita Lee, an octogenarian activist and member of President Barack Obama's Advisory Commission on Asian Americans and Pacific Islanders. But Hillary's own stock soared among Filipinos when, as a senator, she supported a proposal to salve a long-running wound and extend full benefits to the families of Filipino second World War veterans. "She has always been a friend of ours, from way back," says Lee.

Political parties tend to think of Nevada as three discrete electorates: Las Vegas, Reno and the rural counties. Las Vegas, which dominates Clark County, is so overwhelmingly Democratic that Clinton can count on a 14 per cent advantage here. The sparsely populated rural counties are staunchly conservative, while in Washoe County, home to Reno, Republicans have a slight advantage.

"Clark County is anywhere from two thirds to three quarters of the vote, depending on turnout, so Democrats just need to get a big lead in Clark County and they can win without getting any other county in the state," says Jon Ralston, a Nevada-based political commentator and talk show host.

That’s why the Clinton campaign is putting such effort into Las Vegas, with particular focus on its sizeable minorities. In 2008, the Hispanic vote, heavily concentrated on Las Vegas, made up 15 per cent of the Nevada electorate. In 2012 it was 18 per cent and this year it could be as high as 20 per cent.

“That cohort is going overwhelmingly against Trump,” says Ralston. “So if you get 20 per cent of the electorate going 80-20 against you, it’s very difficult to win.”

Donor refusal

These demographic trends present the Donald Trump campaign with a formidable challenge, but the Republicans' failure to match Clinton's ground game has compounded the party's problems here.

Whereas Clinton has been able to draw on the well-oiled Democratic machine of Senator Harry Reid, one that served Obama well in the last two presidential elections, Trump's field operation is virtually non-existent – a problem the Republican National Committee has attempted to remedy by flying outside staffers in to strengthen the campaign.

Even more galling for the Republicans has been the refusal of one of the party's biggest donors, the Las Vegas casino magnate Sheldon Adelson, to put any significant funds into the Trump campaign in the state. "That has hurt them greatly," says Ralston.

When the voter registration deadline passed on Tuesday, the Democrats had an 85,000-person lead over the Republicans in Nevada. That represents almost six per cent of the state’s electorate. “Registration is not destiny,” says Ralston, “but it does mean something.” If the Clinton campaign manages to turn those names into votes, it will mean victory.