Hillary Clinton savoured her crushing victory on Sunday over Bernie Sanders in the South Carolina primary – a win that makes another striking showing at the polls this week look all but inevitable, and with it a smoother road toward the Democratic party nomination.

Hillary Clinton may have hit her stride — but don't write Sanders off just yet | Lucia Graves Read more

Clinton’s victory, with a remarkable 74%-26% margin, gave her the confidence to pass up appearing on the Sunday political talkshows – usually a crucial ritual for candidates with a pressing need to get a message out. Instead she headed straight for campaign events in Tennessee.

The road-worn candidate had made her case the night before, after South Carolina’s unequivocal numbers came in. Her speech made clear that she was already looking beyond the primary against Sanders and towards a race against the Republican frontrunner, Donald Trump.

“We don’t need to make America great again,” she said, alluding to the billionaire’s oft-repeated slogan. “America’s never stopped being great. But we do need to make America whole again. Instead of building walls, we need to be breaking barriers.”

Clinton also paid tribute to five mothers of African American men and women killed by police officers, or in cases with racial overtones, and thanked them for their help campaigning with her in the Palmetto State. She read the names of those young men and women – Eric Garner, Trayvon Martin, Sandra Bland – and vowed to address civil rights and criminal justice reform at a national level.

Clinton did aim some barbs Sanders’ way, not least when she paid lengthy tribute to the “grassroots donors … powering our campaign” – a pointed comparison to Sanders’ oft-touted reliance on small, individual donations, and his lack of Wall Street support. She also alluded to Sanders’ intense focus on inequality and the financial industry, saying that this was not a “single-issue” campaign.

But her speech came to a crescendo with an appeal for common decency amid a presidential race that, on the Republican side at least, has sorely lacked it.

“I know it sometimes seems a little odd for someone running for president these days, in this time, to say we need more love and kindness in America,” Clinton said. “But I’m telling you from the bottom of my heart, we do.”

Sanders, meanwhile, vowed that his road to the nomination was still open, particularly if he can pull off a strong showing after the southern polls next week in states where African Americans strongly support his rival. In South Carolina, Clinton won a whopping 84% of black voters.

Sanders went on TV after his defeat to concede that he’d been roundly defeated. “I won’t tell you we didn’t get beaten and beaten badly in South Carolina,” he said, “but that’s about as bad as it’s going to get”.

But Sanders said he remains confident there was still time on the long primary road ahead. He predicted wins in California, New York and among a “good share” of the 800 party delegates up for grabs on Tuesday. “The point is our message is resonating with people.”

That may be true – even in South Carolina, Sanders did well with young voters who identified themselves as independent – but as he campaigns in Texas, he must also know he needs to find some success or risk ceding the remnainder of his momentum to Clinton.

On the other side of the political race, a buoyant Donald Trump skipped over concerns that he had not strongly denounced a former Ku Klux Klan grand wizard, David Duke, who had endorsed the developer and TV star earlier this month.

“I don’t know anything about what you’re even talking about with white supremacy or white supremacists,” Trump said on CNN. “If you would send me a list of the groups, I will do research on them, and certainly I would disavow if I thought there was something wrong.” He later tweeted an emphatic disavowal.

But the rollercoaster of the Republican primary, which has already twisted the party into knots, showed no sign that it would slow down. Senator Ted Cruz, who may lose in his home state of Texas to Trump on Tuesday, speculated about links between Trump’s business dealings in the 1990s and organised crime.

Citing “numerous reports of Donald’s business dealings with the mob, with the mafia”, Cruz accused his rival of hiring “S&A construction, owned by ‘Fat Tony’ Salerno, a mobster who is in jail” to supply concrete to his casino developments in Atlantic City, New Jersey.

“That has been reported in multiple media outlets,” Cruz said, before returning to a more conventional line of attack: “We don’t know what it is that he’s hiding in his tax returns.”

Trump, still celebrating an endorsement from the New Jersey governor, Chris Christie, says he won’t release his returns until an IRS audit is complete. “I’ve been under audit for 10 or 12 years. It’s not a fair situation,” he said on Sunday.

“Why am I audited? Maybe it’s because I love the Tea Party? But until that audit is complete, I’m not going to show anything.”

His new sidekick Christie said their numerous areas of disagreement, from immigration to social security reform to banning Muslims from entering the US, would be smoothed over in time.

“I ran against the guy, so of course I disagreed with him on some things,” he said on ABC.

The disagreements, he added, were minor compared with what he said was going to happen when Hillary Clinton became the Democratic nominee. “She’s moving so far to the left to beat Bernie Sanders. I don’t know which one is the socialist,” Christie said.

And Florida senator Marco Rubio, still without a state win, maintained that he could win the nomination without a first-place victory in the coming elections.

Asked whether he could win without claiming any states, Rubio said: “That’s not the plan, by the way, but sure. ’Cause we’re going to pick up a lot of delegates.”

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He said voters would realise the dangers of electing Trump in due time: “People will see what they’re about to fall con to, and then we will start to win states, and that includes Florida.”

But the increased clarity on both sides of the race has exposed both the underdogs’ anxieties and some actual delegate mathematics.

That calculus, which gives Clinton 544 delegates and Sanders 85, made a gesture by Hawaii representative Tulsi Gabbard look futile on Sunday. Gabbard resigned from her post as vice-chair of the Democratic National Committee to throw her support behind the senator from Vermont.

Gabbard, an Iraq war veteran, said her decision was motivated by the need to have a commander-in-chief “who has foresight, who exercises good judgment”.

The good judgment of her chosen candidate may be tested on Tuesday; rumours from the campaign trail suggested the Vermont senator may concede if the numbers go decisively against him this week.