US states Alaska, Hawaii and Washington take their turn voting Saturday in the Democratic presidential nominating contest, with Hillary Clinton unlikely to deliver a knockout blow against resilient rival Bernie Sanders.
The trio of western caucuses marks a chance for Vermont Senator Sanders, a self-described democratic socialist, to chisel away at Clinton's formidable lead in the delegate count.
Sanders gave a rousing rendition of his standard stump speech late Friday in Seattle, Washington, just hours ahead of the caucus there, inveighing against police brutality, a too-low minimum wage, and soaring student debt and other ills.
"Real change historically always takes place from the bottom on up when millions of people come together," Sanders said to applause and cheers from the crowd in Seattle's Safeco baseball stadium.
"We need a political revolution!"
But even if the insurgent candidate makes a clean sweep of Saturday's votes, he still has a steep climb to get within striking distance of Clinton.
She has a commanding lead in the delegate race with 1711, including super-delegates who are un-elected by voters, compared to 952 for Sanders, according to a CNN count.
To win the Democratic nomination, 2,383 delegates are needed.
On the campaign trail, the former secretary of state has already shifted her focus toward November's general election.
Clinton delivered a somber counterterrorism speech Wednesday in the aftermath of deadly attacks in Brussels, using it as an opportunity to launch vigorous assaults on Republican candidates Donald Trump and Ted Cruz and warn that their "reckless" foreign policies would harm US interests.
"We need to rely on what actually works," she said, "not bluster that alienates our partners and doesn't make us any safer."
Clinton has a commanding lead in the delegate race: 1711, including super-delegates who are un-elected by voters, compared to 951 for Sanders, according to a CNN count.
But Sanders has refused to throw in the towel, repeatedly stressing that his grassroots campaign is heading all the way to the nominating convention in Philadelphia in July.
Washington is Saturday's biggest prize with 101 pledged delegates up for grabs. When Sanders brought his message of "political revolution" to a Seattle, Washington arena last Sunday, an estimated 17,000 people showed up.
The Pacific island state of Hawaii, birthplace of President Barack Obama, has 25 delegates at stake. Remote Alaska has 16.
There has been little reliable polling in the three states, but at least in Washington Sanders can take comfort in previous results.
Hillary's husband Bill Clinton placed fourth in Washington in the 1992 nominations race, while Democrats there overwhelmingly backed Obama over Hillary Clinton in 2008.
Narrowing the gap
Saturday's three contests are caucuses, essentially neighbourhood meetings where voters can discuss political platforms and debate the merits of the candidates.
Since they generally require voters to show up in person rather than mailing primary ballots, the format favors Sanders, whose supporters have consistently shown more grass-roots enthusiasm.
His campaign pointed to a new poll released Thursday that shows Clinton, who entered the race as the Democrats' overwhelming favorite, deadlocked with Sanders.
A Bloomberg Politics national poll found Sanders actually inching ahead of Clinton, 49 to 48 per cent, among Democrats who voted or are likely to vote in the nominating contests.
A series of recent polls has shown Sanders consistently doing better than Clinton against Republicans Trump, Cruz and Ohio Governor John Kasich.
Millennials and first-time voters have been flocking to Sanders's message of economic equality, universal health care, and his call to reduce the influence of billionaires on the campaign finance system.
"They're seeing almost all new income and wealth going to the top one percent," Sanders told online program The Young Turks late Wednesday.
"And no matter whether you're a conservative or a progressive, you know what? You think that sucks, you think that's not what American democracy is about," he added. "And I find a lot of people are coming together on that."
But the delegate math still dramatically favors Clinton. According to RealClearPolitics poll averages, in the remaining states with the three largest delegate allocations -- California, New York and Pennsylvania -- Clinton's lead Sanders by nine points, 34 points and 28 points respectively.