More than 200 Native Americans signed a letter asking Elizabeth Warren to fully retract her claims of Native American ancestry, the Los Angeles Times reports.

Why it matters: The authors, who include prominent activists like Daniel Heath Justice and Rebecca Nagle, write that her actions "have normalized white people claiming to be Native, and perpetuated a dangerous misunderstanding of tribal sovereignty."

House Majority Whip Jim Clyburn (D-S.C.), the highest-ranking black member of Congress, endorsed former Vice President Joe Biden Wednesday, days before South Carolina's primary.

Why it matters: Clyburn wields tremendous political influence in South Carolina, where a weak showing by Biden could be the death blow to his presidential campaign. Biden has long viewed the state as his firewall due to his strong support among black voters, who make up about 60% of South Carolina's Democratic electorate.

Some climate and energy legislation could actually reach the finish line this year in a divided Congress, according to a new analysis from the think tank Third Way.

Driving the news: Third Way says that's not crazy, pointing to a series of modest measures where "priorities are aligned" on both sides of Capitol Hill.

Democrats finally debated health care subjects other than Medicare for All on Tuesday night.

Why it matters: We have a much wider range of health care problems than political debates usually suggest. Discussing rural Americans' lack of access to health care may not be as exciting as debating whether to do away with private insurance, but it's a subject that many voters struggle with every day.

Pro-Trump super PAC America First Action is preparing to unleash a series of targeted, swing-state attacks on the Democrat most likely to face President Trump after Super Tuesday, people familiar with the group's plans tell me in an exclusive preview of its strategy.

The state of play: The group has been tracking favorable/unfavorable ratings in Florida, Georgia, Michigan, North Carolina, Ohio and Pennsylvania for 2020 candidates Joe Biden, Bernie Sanders, Elizabeth Warren, Pete Buttigieg and Michael Bloomberg — under the theory that if Trump wins each of these six states he would win re-election.

For the second straight week, Bernie Sanders has hit the high watermark for online attention in the Democratic primary, according to data from NewsWhip provided exclusively to Axios.

Why it matters: It's not just quantity. The sentiment of the top stories about Sanders has been more positive than his top Democratic rivals — particularly Michael Bloomberg, whose recent online attention has been overwhelmingly negative.

Rep. Ilhan Omar (D-Minn.) announced Tuesday details of her upcoming memoir, due to be published in May, which publisher Dey Street Books called an "inspiring coming of age story of a refugee."

Why it matters: The 38-year-old freshman Democrat became in 2018 the first Somali-American ever elected to Congress — and she's one of the first two Muslim women elected to Congress, along with fellow "squad" member Rashida Tlaib (D-Mich.).

Go deeper: Ilhan Omar makes history as first Somali-American elected to Congress

Candidates spoke past their allotted time, punched the air, talked over each other and at times looked into the camera and directly addressed the American public and Russian President Vladimir Putin at Tuesday night's Democratic presidential debate in South Carolina, the last before Saturday's primary and Super Tuesday a few days following.

Why it matters: South Carolina's contest on Saturday is a measure of African-American support for the 2020 contenders. It's the make-or-break state for former Vice President Joe Biden after he underperformed in the first three contests. It's also a chance to check Sen. Bernie Sanders' momentum, which has eaten into Biden's lead in the state and propelled Sanders to the front of the pack.

Sen. Bernie Sanders wanted to keep his momentum after winning contests in New Hampshire and Nevada, while former Vice President Joe Biden hoped to keep his own campaign alive. The other five candidates were just trying to hang on.

What's happening: Seven contenders for the Democratic presidential nomination were in Charleston, South Carolina, for the 10th debate, just days before the South Carolina primary and a week before Super Tuesday. They spoke, sometimes over each other, about health care, Russian interference in the election, foreign policy, the economy, gun control, marijuana, education and race.

The 10th Democratic debate was billed as the most consequential of the primary thus far, but Tuesday night's high-stakes affair was at times awkward and unfocused as moderators struggled to rein in candidates desperate to make one last splash before Saturday's primary in South Carolina and Super Tuesday.

The big picture: After cementing himself as the Democratic favorite with a sweeping win in Nevada, Sen. Bernie Sanders came under fire as the front-runner for the first time on the debate stage. Former New York Mayor Michael Bloomberg, who will be on the ballot for the first time next Tuesday, was a progressive foil once again, but he appeared more prepared after taking a drubbing at the Nevada debate.

Sen. Bernie Sanders mocked President Trump's response to the novel coronavirus Tuesday at the Democratic debate.

What they're saying:

" In the White House today, we have a self-described great genius — self-described — and this great genius has told us that this coronavirus is going to end in two months. April is the magical date that this great scientist we have in the White House has determined — I wish I was kidding, that is what he said."

Former Mayor Michael Bloomberg on the debate stage Tuesday denied telling a former employee to terminate her pregnancy.

Catch up quick: Per the Washington Post, a former saleswoman has alleged workplace discrimination against Bloomberg and his company and says Bloomberg told her to "kill it" when he learned she was pregnant. Bloomberg denied the allegation under oath and entered a confidential settlement with the woman.

Sen. Bernie Sanders sent a message to Russian President Vladimir Putin on the debate stage Tuesday, stating, "If I'm president of the United States, trust me, you're not going to interfere in any more American elections."

The big picture: It was unveiled last week that Russia has been interfering to boost Sanders' campaigns in an apparent attempt to strengthen President Trump's bid for reelection. Former New York Mayor Michael Bloomberg said that "Vladimir Putin thinks that Donald Trump should be president of the United States, and that's why Russia is helping [Sanders] get elected.