California Congressman Adam Schiff refuted the president's claim, and said Trump is "unwilling" to stop Russian interference.
David Plouffe said the idea some Democrats would choose a contested convention over supporting Vermont Senator Bernie Sanders' nomination is "preposterous."
Vermont Senator Bernie Sanders was accused of "egomania" and accepting Russian assistance Saturday, after he remarked that neither the Democratic Party nor the Republican Party can stop his 2020 presidential campaign.
During an appearance on Fox News, the former House Speaker said that Bernie Sanders probably will not win the presidency.
Morgan State journalism professor Jason Johnson claimed "racist, liberal white" Americans support Vermont Senator Bernie Sanders and drew backlash Friday for saying only "misfit black girls" defend his campaign.
Sen. Bernie Sanders is leading the field in the California Democratic primary race, with Sen. Elizabeth Warren in second place, according to a new poll.
Russia is believed to be meddling again in the 2020 presidential election, according to intelligence reports.
"We call on Bernie Sanders to immediately condemn these attacks," Mike Bloomberg's campaign manager said.
Bloomberg was criticized for being unprepared for the debate, and Trump said that performance made him hope the former New York City is the Democratic nominee.
The president's son took aim at the former mayor of New York City's performance during the Democratic debate in Las Vegas.
Sanders told CNN that he believed the former president would play a "vigorous" role in the 2020 campaign.
The billionaire former New York City mayor has pumped $463.8 million into his self-funded campaign so far.
Super Tuesday—when voters in 14 states and one U.S. territory go to the polls—could see the Vermont senator establish an unassailable lead.
The gun control record of Senator Bernie Sanders was heavily criticized by former New York City Mayor Mike Bloomberg in a series of tweets on Thursday night.
Minnesota Attorney General Keith Ellison said that he'd never seen Bernie Sanders supporters "being unusually mean or rude," and requested evidence of bad behavior.
"Warren was not mean, nor angry. She was effective," Representative Alexandria Ocasio-Cortez tweeted.
PredictIt, a prediction site that values candidates as stocks, has Sanders with a sizable lead over all other candidates to win the nomination.
Sheldon Adelson, whose wealth is estimated at $39.2 billion, is one of the Republican Party's most prominent donors.
"He is a threat because he's already dropped $400 million in this campaign," said the Massachusetts senator.
Fears that a Donald Trump vs. Bernie Sanders match-up could set the presidential race up for a referendum on capitalism vs. socialism are overblown, strategists said. The picture is more nuanced.
"We're not even in the top ten," former South Bend, Indiana Mayor Pete Buttigieg said.
10 polls released since Monday show Sanders as the Democratic frontrunner, with the senator's percentage of supporters ranging from the mid 20s to early 30s.
Lester Holt, Chuck Todd, Hallie Jackson, Vanessa Hauc and Jon Ralston will moderate the debate in Las Vegas.
"Mayor Bloomberg is profoundly unvetted. Story after story has come out and the sheer volume of these stories is disturbing," a senior Biden campaign official said.
The results showing most Democratic voters believed Sanders would beat Trump in the general election were released three days before the Nevada caucuses.
The senator from Vermont has seen an uptick in support from hispanic voters, with a plurality of 42 percent of the demographic backing his candidacy.
The Center for Economic and Policy Research suggests scheme that pays benefits to one fifth of U.S. population should be changed.
Among Hispanic voters, Vermont Sen. Bernie Sanders saw 41 percent of support in a recent SurveyUSA poll.
The new poll found the Vermont senator was the only Democratic primary candidate to beat Donald Trump in a hypothetical head-to-head.