Political junkies are focused on Donald Trump, but Hillary Clinton’s weakness remains a huge story. Her support among Iowa’s likely Democratic caucusgoers has dropped to 37%, down 20 points since May, according to an Aug. 26 Des Moines Register/Bloomberg Politics poll. Meanwhile, Vermont Sen. Bernie Sanders is up 16 points to 30%, and Vice President Joe Biden, who isn’t even running, is up six points to 14%.
The poll caused great consternation among Mrs. Clinton’s supporters, as it should have. Some of her advocates tried to claim that the survey contained good news, in that the former secretary of state’s favorable rating among Democratic caucusgoers remained at 77%.
But if Mrs. Clinton’s favorables remained high while she hemorrhaged support, then Iowa Democrats are moving to Mr. Sanders not because they dislike her but because she doesn’t excite them, and they like him more. That too was polled. Only 2% of Mr. Sanders’s backers said that their decision to support him was because they don’t support Mrs. Clinton.
But is there a Democrat who—absent something extraordinary, say, Mrs. Clinton’s indictment over mishandling classified information on her private email account—can beat her for the nomination?
If this is the field, the answer is probably no. Former Maryland Gov. Martin O’Malley, former Virginia Sen. Jim Webb and former Rhode Island Gov. Lincoln Chafee are vying to avoid being asterisks in the polls.
Things will probably get worse for Mrs. Clinton in the short term. It’s possible, even likely, that she will lose both the Feb. 1 Iowa caucus and the New Hampshire primary eight days later. Mr. Sanders will appeal in a state like Iowa, where there is a strong left-wing sentiment, and the caucus format is dominated by more ideologically committed activists. He could carry New Hampshire in a multicandidate field.
But then the calendar becomes Mrs. Clinton’s friend. South Carolina and Nevada are next. Neither is fertile ground for Mr. Sanders, the self-proclaimed democratic socialist. On March 1 come primaries in Arkansas, Massachusetts, Oklahoma, Tennessee and Texas, all states Mrs. Clinton carried in 2008. She will probably fare well on super Tuesday again, except perhaps in Massachusetts, a next-door neighbor to Mr. Sanders’s home state.
There also will be primaries that day in Alabama, Georgia, North Carolina, Vermont and Virginia, states that then-Sen. Barack Obama carried in 2008. Vermont will go for its favorite son, but Mrs. Clinton stands a better chance than Mr. Sanders in the others if she has the backing of black Democratic leaders who voted for Mr. Obama seven years ago.
Competing in these primaries will be expensive. A reasonable flight of three or four weeks of television ads in those states will cost north of $30 million, even at the low rates candidates are guaranteed by the FCC, and more if the ads are bought by a super PAC. Mrs. Clinton is likely to have the cash; Mr. Sanders is not, even if his fundraising gets a boost from early victories.
The contests between March 5 and March 15 appear inhospitable for Mr. Sanders as well. Mrs. Clinton carried Florida, Michigan and Ohio in 2008 and virtually tied in Missouri, even with Sen. Claire McCaskill helping out Mr. Obama. This time she will be helping Hillary. Mr. Obama carried his home state of Illinois, Kansas (where he claimed family ties), Louisiana and Mississippi. All four, especially the Southern states, seem better turf for Mrs. Clinton this time.
There are also March caucuses in Colorado, Minnesota and Nebraska. Unprepared for most caucuses in 2008, Mrs. Clinton got walloped. Even if she’s learned a lesson, Mr. Sanders could be competitive in parts of Colorado and Minnesota.
Mr. Sanders’s problem is simply that there aren’t enough left-wing enclaves like Portland and Berkeley, Madison and Ann Arbor, Burlington and Boulder for him to beat her for the nomination.
Could Vice President Joe Biden, though? Mr. Biden would do better in the blue-collar parts of Missouri and Michigan than Mr. Sanders—and maybe even Mrs. Clinton. But once the contest runs through the South, he would have to pick up a substantial part of the black vote. It’s one thing to vacation in South Carolina, as Mr. Biden does. It’s another thing to generate the level of support that Mr. Obama enjoyed there in 2008.
Still, the more candidates in the Democratic race, the more Mrs. Clinton’s numbers will drop, and the more unconventional the nominating process will become. And in this election, unconventional is doing better than expected.
A version of this article appeared September 3, 2015, in the U.S. edition of The Wall Street Journal, with the headline Hillary Could Lose Iowa—And New Hampshire and online at WSJ.com.