DES MOINES, Iowa — The ever-unpredictable presidential race shifted Tuesday from the snowy plains of Iowa to the frigid forests of New Hampshire, but the caucus victors are keeping one eye on the friendlier demographics in the South.

Republican Ted Cruz’s solid victory and Democrat Hillary Clinton’s razor-thin win in the nation’s first presidential vote set up both to be a formidable force across the region when voting begins later this month in South Carolina and sweeps through Georgia and other neighbors March 1.

Both must first face voters in the Granite State, where a blend of independent-minded and libertarian voters gives billionaire Donald Trump big leads in Republican polls. Vermont U.S. Sen. Bernie Sanders, who declared the Iowa results to be a “virtual tie,” has the built-in advantage of holding public office in New Hampshire’s neighbor for more than three decades.

New Hampshire has historically favored more moderate candidates than Iowa, and more than 40 percent of the state’s voters are not registered in any political party, giving them the power to choose which party’s primary to vote in. Polls show well over half of Republican voters have yet to make up their minds.

A recent WMUR/CNN poll of New Hampshire Republicans by the University of New Hampshire Survey Center had Trump with 30 percent, ahead of Cruz at 12 percent, followed by Rubio at 11 percent.

On the Democratic side, Sanders led Clinton, 57 percent to 34 percent. More than 40 percent of Democrats said they had not definitely decided whom they will support. The Democrats will debate Thursday evening, a late addition to the debate schedule.

The Republicans will debate for the eighth time Saturday.

THE FRONT-RUNNERS’ PLANS

But Cruz and Clinton want to position themselves as the candidates to beat when the race moves south. Cruz, a U.S. senator from Texas, was set to stump Tuesday before a crowd in South Carolina, where culturally conservative and evangelical voters mirror the Republican electorate who fueled his win in Iowa.

Clinton’s campaign will send her husband, former President Bill Clinton, to shore up her support with the heavily black Democratic electorate with a visit to Columbia on Wednesday. Unlike Iowa’s overwhelmingly white Democratic voting bloc, across the South the party is dominated by African-Americans, many of whom have long ties to the Clinton family.

And U.S. Sen. Marco Rubio of Florida, who won over late-breaking voters to finish a surprisingly strong third in Iowa, picked up a key endorsement in South Carolina as he works to emerge as the mainstream alternative to the top Republican candidates.

Republicans vote on Feb. 20 in South Carolina, and Democrats go to the polls on Feb. 27.

The caucuses are as much about who lost as they are about who won. And for Trump, who surged in the polls until the first votes were cast in cramped gyms and churches across Iowa, Monday’s bitter defeat raised new questions about his staying power.

The longtime national front-runner failed to attract even one-quarter of Republican support in a state whose voters have been inundated for months with his anti-establishment, tough-talking message.

What’s worse for Trump is his appeal in Iowa always centered on whether he could mobilize first-time voters who had never caucused before. But a record Republican turnout fueled by new caucus-goers – a CBS exit poll showed 45 percent of Republican votes were from first-timers – didn’t help him.

He cast his second-place showing as a “long-shot great finish” against rivals who vastly outspent him in Iowa, and he downplayed criticism that his brash plans to remake Washington fell flat with religious conservatives.

What’s clear, however, is that Trump failed to convert the thousands of Iowans who packed his rallies and told pollsters they would caucus for him into actual voters when it mattered. And, with double-digit leads in New Hampshire, anything short of a victory next week would be disastrous for his campaign.

WINNING THE SUPPORT OF BLACKS

For Sanders, though, the impact of the photo finish with Clinton is harder to gauge.

Just weeks ago, few expected him to mount a serious challenge against the former secretary of state and her celebrated get-out-the-vote organization in Iowa. But huge crowds attracted by his vows to expand federal government and pump new funding into jobs and infrastructure programs helped him pull neck-and-neck with Clinton in the final days before the caucus.

And then, despite Iowa’s overwhelmingly white and liberal base of Democratic voters – the bloc Sanders is supposed to own – he still lost to Clinton.

State Rep. LaDawn Jones, an Atlanta Democrat who endorsed Sanders, said he can bounce back in the South by emphasizing support for policies that matter to African-American families.

“Criminal justice reform, free college and health care for all and taking away the power from Wall Street are black issues,” she said.

Clinton is working to reinforce her black support across the South, where polls show her with commanding leads over Sanders among African-American voters. Bill Clinton’s visit to Allen University, a historically black college in Columbia, is his second stop in South Carolina in three weeks. And Atlanta Mayor Kasim Reed, a Clinton supporter, predicted she would “eviscerate” Sanders in the state.

Republicans began tiptoeing back to the region as well. Rubio garnered the endorsement of U.S. Sen. Tim Scott, R-S.C., who cast him as the Republicans’ best chance in November.

“We have one shot in 2016 to beat Hillary Clinton and that shot is Marco Rubio,” Scott said.

Cruz was campaigning Tuesday in upstate South Carolina, the Greenville News reported, and would be endorsed by U.S. Rep. Jeff Duncan, a tea party Republican elected during the 2010 surge.

Then there was former Pennsylvania U.S. Sen. Rick Santorum, the victor in Iowa’s 2012 caucus, who faced mounting pressure to bow out of the race after a dismal showing Monday.

He pinned his hopes on South Carolina’s Feb. 20 Republican Party vote, announcing a 46-county tour across the state. And, in a naked play for the hearts of SEC primary voters, he compared himself to the University of Alabama’s championship football coach.

“I’m Nick Saban in this race,” Santorum said. “Come on, guys, you want to win championships! Let’s do it!”

The Associated Press contributed to this report.