It was a raw, windswept afternoon when Hillary Clinton appeared on what would have to pass for a stage. There were no warm-up chants, no triumphalist campaign songs, no celebrity supporters, just five local women awkwardly flapping blue Hillary signs.

The audience at this Indian reservation - about 200 counting 14 students on a class trip from Massachusetts and their teacher, who said they were all Barack Obama supporters - was so small Clinton did not even attempt the politician's hoax of pointing to faces in fake delight.

This is what it looks like for Clinton at the end, the last gasps of a dying presidential campaign. When she launched her campaign in January last year, she cast herself as the inevitable Democratic nominee. "I'm in it to win it," she said.

Now Obama looks like the inevitable candidate. Clinton's chances of a miracle recovery evaporated on Saturday when the Democratic party decided to recognise primaries in Michigan and Florida, but halve their voting power at the party's nominating convention.

Clinton has three more events in South Dakota today before her campaign splutters to a final stop. Obama is expected to carry South Dakota as well as Montana when the two states hold the final contests of this primary season tomorrow.

A lifetime's worth of ambitions, 16 years of acquaintances in the Democratic party establishment, 16 grinding months of rallies and debates, and $215m (£108m) in campaign funds, all now are exhausted.

So too was Clinton. Her face as she took the stage at the Pine Ridge reservation was drained of colour. People took pictures anyway. Those old enough to remember are still talking about the late Robert F Kennedy's visit to this remote outpost during the 1968 campaign.

They were already talking about Clinton's campaign in the same way: history. "I'm just curious to see her in person," said Beverly Tuttle, a grandmother from nearby Porcupine. That was as far as it went. Tuttle was voting for Obama. "I'm looking at her more like a celebrity than candidate," she said.

Clinton still has ardent supporters, even in a remote location such as Kyle (population 1,000). They just have been swifter than she has in recognising defeat. "She should be vice-president," said Tangerine LeBeau, who is just 18 and will be voting for the very first time.

If Clinton was disappointed at the small size of the crowd after a two-hour drive across the South Dakota Badlands, she barely let on.

Each day, even in this terminal stage, brings a full schedule of campaigning for all three Clintons: Bill, Hillary and Chelsea. Campaign staff produce policy memos and instant reactions to statements from John McCain, the Republican candidate. Emails go out to supporters asking for funds. The activity is highly unlikely to prolong the life of her presidential campaign, but Clinton seems determined to go down fighting for every last vote.

In South Dakota, where native Americans make up nearly 9% of the population, she adapted her standard stump speech to promise more funding for government programmes and a higher profile for the official dealing with Native American issues. Under a Clinton White House, she said, the reservation, one of the poorest areas of the country, could become the "Saudi Arabia of wind power".

And Clinton showed no sign of letting go of the idea that she could still win the nomination. Her smile ever widening, she took audiences through a surreal mathematical discourse on how she could conceivably still emerge as the Democratic nominee at the party's convention in August.

"Since February 20 I have won more contests, won more votes, won more delegates," she told a rally in Rapid City last week.

But, of course, Clinton has already all but lost, and the crowd knew it. "Realistically, it's not going to happen. The numbers aren't there," said Richard Stalder, a mental health worker. "It's important for me that she is strong, that she can stand in there."

Strength and resolve can only carry Clinton so far. Obama has powerful backers in the west. Tom Daschle, a South Dakota native who was once Senate majority leader, was one of Obama's earliest supporters. Obama's deputy campaign manager is also from South Dakota.

Despite the courtship by the Clintons, Obama was endorsed by the entire tribal leadership of South Dakota, and was adopted as a son of the Crow tribe in Montana. Obama also has the money to pour resources into South Dakota and Montana. Clinton's coffers are beyond empty. Her campaign, now $20m in debt, has no money for the prime venues that she favoured in the early months of the campaign. Almost all of her campaign events are held outdoors despite unpredictable weather. At one rally, Clinton's only stage prop was a giant cottonwood tree.

She has little money to get voters to the polls - a huge liability on the reservations where poverty and long distances depress turnout. Clinton also has little money for advertising. Her first television ad in South Dakota went on air less than a week ago. The ad, despite her own insolvent campaign, attacks President George Bush for running up the national debt.

Her entourage on the campaign trail is similarly shrunk. Her assistant, Huma Abedin, once deemed so glamorous she was given a Vogue photospread, remains along with a couple of other aides. News outlets have scaled back their coverage. Camera crews once used to jostling for positions on risers now have yards of space to themselves.

When Clinton tagged along on a journalists' sightseeing tour of Mount Rushmore, reporters did not welcome the extra access to a would-be president. They blogged about how Clinton's presence turned a few hours' break into work.

But it's possible to forget all of that, even in a modest crowd. At the end of her big rally in South Dakota last week, Clinton worked the rope line long after people had dispersed, stretching out to every last hand, unwilling to let go.