America's presidential candidates criss-crossed the country in a frenzied last-minute dash for support ahead of today's Super Tuesday primaries and caucuses, with California emerging as the key battleground for both parties in a thrilling, boundlessly unpredictable race to the finish.
For the Democrats, Barack Obama is hoping the Golden State is where he can become the giant-slayer extraordinaire; opinion polls show him edging into a slight lead over Hillary Clinton just one week after he appeared to be trailing by a double-digit margin.
Everything has gone his way in the past few days, starting with the momentum from his trouncing of Senator Clinton in South Carolina on 29 January and the subsequent endorsement of Teddy Kennedy, who has campaigned energetically for him.
Since then, he has been embraced by the Los Angeles Times, the biggest paper on the west coast, and La Opinion, the largest Spanish-language newspaper in the state. Many union leaders and key donors backing John Edwards have come out for him. Senator Obama is fielding a grassroots ground campaign, staffed overwhelmingly by unpaid volunteers, of unprecedented size and reach. And he even won the unlikeliest of endorsements, from Maria Shriver, the wife of California's Republican governor, Arnold Schwarzenegger.
For the Republicans, Mitt Romney yesterday seized on one poll putting him eight points in front of John McCain in California and immediately arranged a last-minute rally in the gritty port city of Long Beach, taking a 6,000-mile round trip out of his way to do so.
Mr Romney's hopes are a longer shot, especially since the national polls show Senator McCain holding a commanding lead of 15 percentage points or more. But he has the backing of many of the most popular conservative radio talk-show hosts, including Rush Limbaugh, who share his view that the independent-thinking Senator McCain isn't a "true conservative".
He is counting on those conservatives to demonstrate passion on his behalf, in a race where the bulk of the passion is on the Democratic, not the Republican, side of the fence. After a Zogby poll put Mr Romney ahead in California, he told reporters: "People there are taking a real close look at the race and it looks like I've got a good shot there."
But the poll results are at variance with the more prestigious Field Poll, which on Sunday had Senator McCain ahead 32 per cent to 24. Most pundits say the continuing presence of Mike Huckabee, the evangelical former governor of Arkansas, is bound to eat into Mr Romney's support. The Romney campaign's best hope is that Huckabee supporters will switch to him for tactical reasons.
The mathematics of the delegate race alone suggest the Republicans are much more likely to settle on a nominee after today than the Democrats. Most of the Republican contests are winner-takes-all, which means that without a significant statewide victory Mr Romney's hopes will be essentially dashed.
The Democratic contests are mostly proportional, based on either statewide polling or on results by congressional district, or some combination of the two. Senator Obama does not need to win California in the same way Mr Romney does. A close second will be good enough to keep the race going towards the next scheduled contests in Nebraska, Texas, Ohio and elsewhere.
The psychological impact of an Obama victory in California would be profound, possibly enough on its own to propel the Illinois senator towards the nomination. Pundits and pollsters agree that all the momentum is heading in his direction, in California and across the country. The biggest question is whether he has enough time to build that momentum into victory.
But the voting timetable risks producing a result voters may regret. "A Clinton win this week," one pundit said, "produced merely by the absurd acceleration of the primary calendar, would leave the Democrats with what might be called a Twilight Zone candidate, a nominee the party rejected but the calendar saved."Reuse content