• Cory Booker has dropped out of the presidential contest.
• Bernie Sanders is criticized for going negative. His campaign has accused Joe Biden of “betraying” black voters (Biden is the first choice of many black voters) and Elizabeth Warren of being the candidate of wealthy white liberals. NBC reports it’s bringing back memories of 2016: “Sanders, his supporters and his surrogates go on the attack; Sanders downplays or dismisses the attacks; and the party becomes more divided.”
• Biden still leads in the endorsement primary, but it’s slow going. Only a third of Democratic governors, senators and representatives have endorsed a candidate. Party leaders may be waiting to see what happens in the first few primaries before making up their minds. Or perhaps this will be like the Republican primary of 2016, when “the” party collectively decided not to decide.
• Michael Bloomberg has said that, even if he loses, his campaign — the biggest and most expensive of the Democratic candidates — will remain in place to help defeat Donald Trump. He has also shot down criticism, notably from Warren, that he’s trying to buy the nomination, saying, “Do you want me to spend more or less?”

Read more

• Jonathan Bernstein argues Biden, Warren, Amy Klobuchar and Pete Buttigieg are all running as coalition-style candidates, which the process tends to reward, whereas Sanders is a factional candidate. Party actors are also skeptical of his proposition to ignore the ideological middle in a general election and run far to Trump’s left.
• Hanna Trudo reports that former president Barack Obama’s lieutenants share those concerns but have yet to mount a concerted opposition.
• Bill Scher argues Iowa matters less than ever. The proof is in the candidates’ travel schedules: with the exception of Klobuchar and John Delaney, they are spending far less time in the state than candidates did in previous elections.
• Nate Silver disagrees, arguing that a win in Iowa would significantly raise a candidate’s chance of winning the nomination. His website, FiveThirtyEight, estimates Biden has a two-in-five chance of winning the nomination, followed by Sanders at one-in-five.
• Rick Wilson, a Republican strategist, warns Democrats are veering too far left to appeal to disaffected Trump voters in swing states such as Florida, Michigan, Pennsylvania and Wisconsin.