Asma Khalid

Cory Booker is a politician who sounds like a preacher.

"We may be down in a valley right now," he said during an Iowa campaign stop this week, "but I promise you, if you stand with me, if you caucus with me, if we stand for that spirit, I promise you, we will get to the mountaintop and we'll do it, because together as Americans, we know we will rise."

Michael Bloomberg, the billionaire former mayor of New York City, entered the Democratic presidential primary a month ago. He's already spent more than $100 million on advertising.

Bloomberg and Tom Steyer, another billionaire in the Democratic contest, have in total spent about $200 million so far, according to Advertising Analytics, a firm that tracks campaign ad expenditures.

This weekend, one of the most high-profile Latinas in Congress, Rep. Alexandria Ocasio-Cortez, is campaigning for Bernie Sanders in Nevada and California.

When Elizabeth Warren arrived in Austin to teach law school at the University of Texas in the 1980s, colleagues say she was nothing close to the unapologetic progressive firebrand voters see today.

"She was quite consistently pro-business," said Calvin Johnson, who taught law school with Warren at the University of Texas. "And I'm sure she would not like to be called 'anti-consumer,' " he added. But, in his view, the future Massachusetts senator was "absolutely anti-consumer" on some positions at the time.

When news broke that California Sen. Kamala Harris was dropping out of the presidential race on Tuesday, some fellow Democratic candidates quickly began ringing alarm bells. Harris was the only nonwhite candidate to have qualified for the next presidential debate on Dec. 19.

"What we're staring at is a DNC debate stage in a few days with no people of color on it, that does not reflect the diversity of our party or our country," former Housing Secretary Julián Castro said. "We need to do better than that."

Updated at 3:25 p.m. ET

California Sen. Kamala Harris is dropping out of the presidential race, citing a lack of funds. She informed her campaign staff of the decision on a conference call and later sent an email to supporters, in which she wrote "my campaign for president simply doesn't have the financial resources we need to continue."

When Pete Buttigieg arrived in England, he was a curious, bookish 23-year-old known to his friends as Peter.

The year was 2005. The Iraq War, unpopular among Buttigieg's college peers, was raging with no end in sight. John Kerry, the Democratic nominee for president, had lost the 2004 election to an increasingly unpopular Republican president.

And Democrats, like Buttigieg, were soul-searching.

Former Massachusetts Gov. Deval Patrick is officially joining the 2020 Democratic presidential race less than three months before voters start casting ballots.

"I admire and respect the candidates in the Democratic field. They bring a richness of ideas and experiences and depth of character that makes me proud to be a Democrat. But if the character of the candidates is an issue in every election, this time is about the character of the country," Patrick said in an announcement video published online Thursday morning.

Sen. Elizabeth Warren has built a reputation as the presidential candidate with a plan for almost anything. Plans are her brand, so much so that her campaign shop sells T-shirts proclaiming "Warren has a plan for that."

About three weeks ago, Vermont Sen. Bernie Sanders had a heart attack that threw his campaign into question. But now, it's more apparent than perhaps at any point in this presidential race that the 78-year-old white-haired politician and his revolution will remain a powerful force in the Democratic primary.

Former Vice President Joe Biden unveiled an ethics plan on Monday that directly targets President Trump, accusing him of creating the "most corrupt administration in modern history." It's a sign the Democratic presidential candidate is ramping up his defense ahead of the fourth Democratic debate in Ohio on Tuesday.