Republicans in Nevada are caucusing Tuesday — with Donald Trump hoping to win his third straight contest. Democrats, meanwhile, are preparing for their largest race so far — in South Carolina. Josh Robin has the latest from the presidential campaign trail.

These aren't promising days for Bernie Sanders.

"We've got a lot of work in front of us," the Vermont Senator said.

His hopes were dashed in Nevada on Saturday, and Sanders is facing a steeper hill this weekend in South Carolina.

Hillary Clinton is poised to romp across the state, according to polls.

The Democratic electorate there Saturday could be mostly African-American...both Sanders, and Clinton are tailoring their messages.

Sanders is telling South Carolinians to think big.

"If we had had that mentality of think small, do you think we'd have an African American as president of this country?" Sanders asked.

And Clinton says she stands with President Obama in a new ad narrated by Morgan Freeman.

Clinton's standing dwarfs Sanders in the delegate count, helped by so-called super delegates or party insiders.

She has 502 total, with Sanders at 70 — 2,382 are needed to win.

Meanwhile, on the other side of the aisle, Donald Trump won South Carolina, and leads the GOP delegate count.

"We're just going one after another," Trump said.

The Republican nominee will need 1,237 delegates to win, and the Manhattan businessman has 67.

Texas Senator Ted Cruz is at 11, Florida Senator Marco Rubio, 10 and Ohio Governor John Kasich is at 5.

There is no Republican super delegate system like in the Democratic Party.

Trump seems to be floating above a spat between Cruz and Rubio — which turned odd Monday.

Cruz fired his national spokesman, who had tweeted an erroneous report that said Rubio disparaged the Bible.

"I had made clear in this campaign that we will conduct this campaign with the very highest standards of integrity," Cruz said.

That's not the reputation that's taken hold, and the firing seemed an attempt for Cruz to regain lost trust.

Meanwhile Rubio hopes a Nevada win, or a clear second-place finish, boosts him to Trump's main contender — the choice of the so-called establishment wing.

"When it comes to our campaign, what happens in Vegas, is not staying in Vegas," Rubio said.