Dr. Ben Carson is the latest Republican to announce he is entering the presidential race.

"I'm willing to be part of the equation, and therefore, I'm announcing my candidacy for president of the United States of America," the retired neurosurgeon told WKRC in Ohio on Sunday. "Many people have suggested to me that I should run for president, even though I'm not a politician."

Carson told WKRC he believes people want him to enter politics because "we are in a severe problem... a problematic situation." He says he is a "reluctant warrior" and thinks it's important to "have enough humility to be able to work with others to recognize you're not necessarily the expert in everything. But you can, with very good advice, make good decisions." He will make an official announcement on Monday. Catherine Garcia

The COVID-19 vaccine is open to all Americans 16 and older as of Monday, and "the Biden administration is trying to get the word out," Jimmy Fallon said on Monday's Tonight Show, skeptically. "Your idea to get kids vaccinated is putting an 80-year-old scientist on TikTok? Good luck with that. You know Biden's old when he's like, 'We need someone young and hip for the Snapchat videos. How about that kid Dr. Fauci?'"

NASA successfully flew a helicopter on Mars, Fallon noted. "The flight lasted a total of 30 seconds. The men on the team said it was a complete success, while the women agreed so they wouldn't hurt anyone's feelings." And "a new poll shows Matthew McConaughey is leading Gov. Greg Abbott by 12 points in a hypothetical matchup for governor of Texas," he said. "When asked if he's actually gonna run for office, McConaughey said 'I might, I might, I might.'"

The Late Show created a clearly unsolicited campaign commercial for McConaughey.

One highlight of Sunday night's star-studded COVID-19 special, featuring Biden and and Barack Obama, was "when Dr. Anthony Fauci was interviewed by actor Matthew McConaughey," Stephen Colbert said on The Late Show. "Wow, the sexiest man alive was interviewed by Matthew McConaughey!" For anyone wondering, he added, "I can say categorically that Matthew McConaughey is not going to run for governor. He's going to drive a Lincoln, talking to himself the entire time."

Colbert made extended, elaborate Anglo-Saxon jokes to mock Rep. Marjorie Taylor Greene's (R-Ga.) short-lived America First Caucus, including a Beowulf zinger.

"President Biden over the weekend attended the confirmation of his grandson," Late Night's Seth Meyer said, "but then Mitch McConnell said it's too close to an election and put all confirmations on hold."

Jimmy Kimmel spent most of his monologue in a mutual fascination loop with MyPillow chief Mike Lindell, but he also had some ideas for promoting COVID-19 vaccines to the Republican and white evangelical men opposed to getting inoculated. "I don't think a TV special or putting Dr. Fauci on Snapchat is going to do anything to convince people, these men who don't want to get the shot," he said. "There's a lot of disinformation out there, and I think the CDC should just stop trying to appeal to common sense and embrace the nonsense." Watch Kimmel Live's PSA below. Peter Weber

At the right-wing news channel One America News Network, "there's still serious doubts about who's actually president," as OAN correspondent Pearson Sharp said in a March 28 report. OAN "has become a kind of Trump TV for the post-Trump age," The New York Times reported Sunday, and some of its "coverage has not had the full support of the staff." One OAN producer, Marty Golingan, said the network had lurched to the right since he joined in 2016.

The "majority" of his colleagues "did not believe the voter fraud claims being run on the air," Golingan told the Times, and "a lot of people said, 'This is insane, and maybe if [Dominion Voting Systems] sue us, we'll stop putting stories like this out.'" He said OAN's news director, Lindsay Oakley, reprimanded him for referring to "President Biden" in news copy.

Golingan was fired Monday. He had told the Times' Rachel Abrams he would wear being sacked as "a badge of honor."

Of 18 current and former OAN staffers Abrams interviewed, 16 said their employer had broadcast reports they consider misleading, inaccurate, or untrue. But several also said they have bills to pay and few other job prospects. "We're not Nazis," one producer told Abrams. "Just, like, everyday people." Peter Weber

President Biden hosted another bipartisan group of 10 lawmakers on Monday to discuss his infrastructure proposal, and once again everyone said the meeting was cordial and respectful, Biden and his guests expressed a willingness to compromise on the size and scope of the bill, and the Republicans said they won't support raising the corporate tax rate to pay for the package.

Biden wants to raise the corporate tax rate to 28 percent, from 21 percent, to fund $2.25 trillion in spending. Sen. Joe Manchin (D-W.Va.) has suggested a 25 percent rate, and there's speculation Democrats will settle around that number. "You could see a 2 or 3 percent increase — maybe not all the way to 28 but 25," Rep. Charlie Crist (D-Fla.), who was at Monday's meeting, told The Wall Street Journal. GOP lawmakers were "more in favor of user fees so that whoever was benefiting from that particular infrastructure project would be paying for it in the long run," said Rep. Carlos Giménez (R-Fla.), another participant.

Sens. Mitt Romney (R-Utah) and John Hoeven (R-N.D.) both said after the meeting they favor paying for new infrastructure with gas taxes, user fees, and other mechanisms that don't hit corporations. "There is broad support for infrastructure, and I believe a bipartisan bill is possible, but we need to find agreement to make these updates in a targeted way that doesn't raise taxes," Hoeven said.

Biden opposes user fees, gas taxes, or any other funding mechanism that hits the middle class, and the opposition from Romney and Hoeven suggests he'll get no GOP support for raising corporate taxes, Axios says. Biden told Republicans he won't wait forever for a counteroffer. "He'd like for the Republicans to, you know, for us to come back with some kind of proposal on infrastructure by about mid-May," Giménez said.

Meanwhile, "progressives are warning the president not to get too attached to his GOP friends," Politico reports. Biden "should approach the negotiations with an open mind and an open heart, but he should not delay," Sen. Elizabeth Warren (D-Mass.) said. "We can't end up months from now with no real progress and no real infrastructure bill."

"I personally don't think the Republicans are serious about addressing the major crises facing this country," added Sen. Bernie Sanders (I-Vt.). "Maybe I'm wrong, but we're certainly not going to wait for an indefinite period of time. ... They have something to say? Now is the time to say it." Peter Weber

The Biden administration is considering measures that would force tobacco companies to reduce the amount of nicotine in all cigarettes to nonaddictive or minimally addictive levels, people familiar with the matter told The Wall Street Journal.

The administration is also weighing whether to ban menthol cigarettes, the Journal reports. Federal data shows that every year, 226 billion cigarettes are sold in the U.S., and about a third are menthol cigarettes. Menthol creates a cooling sensation in the throat, making menthol cigarettes an attractive product for young people and new smokers, and the Centers for Disease Control and Prevention says some studies have shown people who smoke menthols have a harder time quitting than those who smoke non-menthol cigarettes.

The Food and Drug Administration and National Institutes of Health have also funded research that showed when nicotine was almost completely removed from cigarettes, smokers were more likely to quit or turn to alternatives that are less harmful, like lozenges or gum, the Journal reports. Annually, 480,000 deaths in the U.S. are linked to cigarettes.

A spokesman for Altria, the maker of Marlboro, told the Journal that any action "must be made on science and evidence and must consider the real-world consequences of such actions, including the growth of an illicit market and the impact on hundreds of thousands of jobs from the farm to local stores across the country." The Journal notes that if the Biden administration goes through with reducing nicotine and banning menthols, it will take years for the policies to go into effect and they will likely face multiple legal challenges. Catherine Garcia

Former Vice President Walter Mondale (D), who died Monday, led a successful effort to reform the filibuster in 1975, when he was a U.S. senator from Minnesota. Before Mondale and James Pearson (R-Kan.) introduced a resolution to reform cloture, the parliamentary mechanism to end a filibuster, at the beginning of the 94th Congress, a two-thirds majority of senators present and voting were needed to break a filibuster; Mondale and Pearson pushed for three-fifths of all senators voting and present.

Senate Rule XXII, which governed cloture, "in its present form, has protected the right of debate at the expense of the right to decide," Mondale told his Senate colleagues. "Rule XXII has significantly impaired the ability of this body to function."

Sen. James Allen (D-Ala.) led the opposition to the measure, and after several rancorous weeks of debate, the Senate agreed to a compromise resolution in which three-fifth of the entire Senate, or 60 senators, had to agree to invoke cloture and thwart a filibuster. That rule still stands for legislative filibusters, though once again there is clamor for reform amid obstruction.

Earlier in his Senate career, Mondale supported a simple majority of 51 senators to quash a filibuster. And he and Pearson briefly set a precedent for a 51-vote cloture, James Wallner explained in 2019. But Mondale had changed his mind by then. "As I see it, it is an issue between the ability to paralyze, on the one hand, and the ability to require full ventilation of an issue, on the other," he said in 1971. "In my opinion, there are crucial issues which demand full consideration by the Senate."

By 2011, Mondale was ready for another round of cloture reform. In 1975, senators hoped lowering the threshold to 60 votes from 67 "would preserve debate and deliberation while avoiding paralysis, and for a while it did," he wrote in a 2011 New York Times op-ed. "But it's now clear that our reform was insufficient for today's more partisan, increasingly gridlocked Senate." Mondale suggested lowering the threshold to 55 votes, or "requiring a filibustering senator to actually speak on the Senate floor for the duration of a filibuster."

"I still would like to keep some of the filibuster," Mondale said in 2013. "I think the Senate should be different from the House. I'm looking for that mysterious line between requiring debate and consultation on the one hand and paralysis on the other hand. ... What we clearly have today is paralysis." Peter Weber

The coronavirus pandemic is continuing to pose an "unprecedented risk" to travelers, the State Department said Monday, and travel advisories are being updated to "outline current issues affecting travelers' health."

The changes "better reflect" the Centers for Disease Control and Prevention's travel health notices, the State Department said, and will "result in a significant increase in the number of countries at Level 4: Do Not Travel, to approximately 80 percent of countries worldwide." The advisories also take into account "logistical factors," the State Department said, like "in-country testing availability and current travel restrictions for U.S. citizens."

Level 4 is the highest travel advisory level, and there are now about three dozen countries with this designation, CNN reports. The CDC is recommending that people delay international travel until they are fully vaccinated against the coronavirus, adding that even those who have been inoculated "are at increased risk for getting and possibly spreading new COVID-19 variants." Catherine Garcia