Sen. Amy Klobuchar (D-Minn.), a Democratic presidential candidate, knocked former New York City Mayor Michael Bloomberg's late entry into the 2020 race.

Klobuchar dismissed the Bloomberg campaign's pitch that the billionaire saw a need for a candidate to take on President Trump.

"I have admiration for the work that he’s done. But I don’t buy this argument that you get in because you say ‘oh everyone else sucks.’ I just don’t," Klobuchar said Sunday on NBC's "Meet the Press."

"I think we have strong candidates. I don’t think that any of the polling or the numbers show that people are dissatisfied with all their candidates. They’re just trying to pick the right one," she added.

In mid-November, a few dozen of the country’s most influential advocates of Medicare-for-all were reviewing details of Sen. Elizabeth Warren’s plan to finance the proposed government-run program when they learned that she had unexpectedly changed her position.

Warren (D-Mass.), who had excited liberals when she initially embraced a Medicare-for-all idea first proposed by rival presidential candidate Sen. Bernie Sanders (I-Vt.), was suggesting a more centrist idea: to delay enactment of the single-payer system and, in the interim, give consumers the choice to opt in. The change might have seemed insignificant to most Americans, but to many in the suburban Washington conference room, Warren’s new stance marked an abrupt retreat, according to several people in attendance.

That moment highlighted the political turbulence that Warren has experienced in recent weeks as she has attempted to extricate herself from a policy dilemma that has blunted her steady rise to the top ranks of the Democratic nominating contest.

Warren had pleased many on the left with proposals to take on entrenched corporate and political power. But she was being warned that support for Medicare-for-all, including the elimination of private health insurance used by more than 150 million Americans, could cost her support among Democrats looking for the strongest candidate to take on President Trump.

Joe Biden is counting on his firewall of support in South Carolina to help him win the 2020 presidential nomination. But Democrats are warning that if the former vice president doesn't perform well in Iowa and New Hampshire, his lead in South Carolina could be in jeopardy.

In recent weeks, Biden has been losing ground in the first two early voting states, according to polling. And if he falls behind Sens. Elizabeth Warren (D-Mass.), Bernie Sanders (I-Vt.) or South Bend, Ind., Mayor Pete Buttigieg, he will have to reassert his case to voters, Democratic strategists and political observers say.

“Bad losses in Iowa and New Hampshire, and some other states, could easily hurt Biden,” said Julian Zelizer, a professor of public affairs and history at Princeton University.

So far, the former vice president has retained strong support from voters in South Carolina. A couple of recent surveys showed approximately one-third of likely voters in the Palmetto State plan to support Biden.