Opinion writer

The latest Monmouth poll from Iowa shows movement in the presidential primary. Former vice president Joe Biden has held his ground since the April poll (27 percent) and leads with 28 percent support of likely caucus-goers. The big shake-up comes with Sen. Elizabeth Warren (D-Mass.) and Sen. Bernie Sanders (I-Vt.). Warren is up from 7 to 19 percent, and Sanders is down from 16 to 9 percent, which matches his worst result in any Iowa poll. In fact, he is now behind Sen. Kamala D. Harris (D-Calif.), who is at 11 percent, and he’s statistically tied with South Bend, Ind., Mayor Pete Buttigieg, who has 8 percent of likely caucus-goers.

Sanders won more than 49 percent of the vote in the 2016 Iowa caucuses. The gigantic drop shows the difference between a binary choice (Sanders vs. Hillary Clinton) and Sanders vs. a bevy of compelling progressives. Sanders, who seems to be rerunning his 2016 campaign (including the yelling part), no longer is a novelty nor even offering the most compelling progressive agenda (that distinction goes to Warren). Sanders’s net favorability has also plummeted from +41 in April to +25; Warren has gone in the other direction, rising from +47 to +62. Perhaps Sanders should smile more.

Joe Biden speaks at the Iowa State Fair on Thursday in Des Moines. (Charlie Neibergall/AP)

Most interesting of all, on health care, a public option (“Allow people to either opt into Medicare or keep their private coverage”) gets 56 percent support, while Medicare-for-all, championed by both Warren and Sanders, gets just 21 percent. If you take the voters at their word, promising to abolish all private health care isn’t a winner with caucus-goers. It’s far from clear, however, whether voters understand precisely where each candidate stands.

As in many other polls, a huge majority (72 percent) want someone to beat President Trump even if they disagree with the candidate on issues. “Biden is the main beneficiary of voters who think that the field is pretty weak against Trump. Among those who feel only one or two candidates have a shot, 41% currently support Biden.”

The poll also shows Sen. Amy Klobuchar (D-Minn.) and billionaire Tom Steyer each at 3 percent, with Sen. Kirsten Gillibrand (D-N.Y.) and Andrew Yang both at 2 percent. Sen. Cory Booker (D-N.J.) is at 1 percent. Beto O’Rourke has collapsed — going from 6 percent to less than 1 percent.

Several caveats are in order. While the poll came after the second debate (good news for Harris, who fared poorly in other post-debate polling), it was completed before the mass shootings in Dayton, Ohio, and El Paso. To the extent voters have been impressed by Booker and O’Rourke (who’ve been rhetorically strong all week), that is not reflected in the polling. And, of course, this is one poll at one moment in time, six months before the caucuses.

Furthermore, with “virtual caucus-goers this time” (who will account for only 10 percent of the total), it’s hard to figure out who will show up in person and who will participate in the virtual caucus. (Monmouth pollsters tell us: “It is unclear, though, how many voters will ultimately choose the virtual option. This group currently represents 20% of all ‘likely caucus-goers’ in Monmouth’s model. The poll is designed to measure the initial candidate preferences of all likely caucus-goers; not the delegates allocated to candidates.”

And finally, under the Democratic National Committee rules, candidates must get at least 15 percent to win any delegates. That means if these numbers hold, only Biden and Warren would win delegates.

With all of that, the best we can say is that Biden is more resilient than critics expected, and Sanders in 2019 is nowhere near as popular as Sanders in 2016. Frankly, at this stage, Warren is eating his lunch.

Read more:

Catherine Rampell: For Trump and his cronies, draining the swamp means ousting experts

Marc Thiessen: There were no ‘safe spaces’ or ‘trigger warnings’ for young people fighting in the Warsaw Uprising

Ben Howe: Evangelicals have abandoned their mission in favor of Trump

Jonathan Capehart: Cory Booker isn’t afraid to do what we all must: Talk about the dark chapters of our history