Former Massachusetts governor Deval Patrick in 2017. (Steven Senne/AP)

Establishment Democrats are worried about Sen. Elizabeth Warren (Mass.) — so worried that they are pushing former New York mayor Michael Bloomberg and former Massachusetts governor Deval Patrick into the race. Those gambits are likely to fail, and not just because late entrants are long shots. These particular candidates treat the symptoms of the Democratic Party’s precarious position rather than the underlying disease.

Late entrants have a horrible track record in Democratic primaries. In 1972, establishmentarians frightened by liberal Sen. George McGovern’s (S.D.) momentum pushed former vice president Hubert Humphrey into the race. Humphrey won a few primaries but ultimately was unable to stop McGovern. Four years later, a new outsider, former Georgia governor Jimmy Carter, had the Beltway types worried. They banked their hopes on California Gov. Jerry Brown, who had not yet descended into flakiness. Once again, Brown won some primaries, but Carter still easily prevailed. Gen. Wesley Clark tried to play a similar role in the 2004 race, entering in mid-September in a vain effort to stop the progressive heartthrob, former Vermont governor Howard Dean. Dean flopped, but not because of Clark, who won only Oklahoma on his way to a forgettable finish.

Sen. Robert F. Kennedy’s (N.Y.) 1968 run for president is the exception that proves the rule. He joined the race following President Lyndon B. Johnson’s decision not to run for reelection following his shockingly small victory margin over Sen. Eugene McCarthy (Minn.) in the New Hampshire primary. McCarthy and Kennedy traded primary wins until California, where Kennedy’s victory seemed to knock McCarthy out of the running until Kennedy was assassinated.

But Kennedy was already a famous figure with a national following from his role in the campaign and administration of his martyred brother, President John F. Kennedy. He also was running in a different environment. He didn’t have to raise hundreds of millions of dollars in a short time or face the current rules that award delegates proportionally to each candidate’s share of the vote. Kennedy won California only by 46-42 percent; that gave him all the state’s delegates, but today he would get only a bit over half of them. Rules like this block a late entrant’s ability to make up ground on their opponents who have accrued delegates in states that have already held their primary contests.

In the present day, establishment Democrats have reason to be worried about Warren. Her policy agenda thrills the party’s far left, but every poll shows it causes problems for her, and the rest of the party, with the national electorate. But you can’t beat something with nothing. That, not the absence of a strong centrist personality, is the problem establishment Democrats need to solve.

Warren is performing well because a very large share of Democratic voters do want uncompromising left-wing policies. They think presidents Barack Obama and Bill Clinton were too timid and conciliatory. They have convinced themselves, as ideologues always do, that their bold ideas will turn out new voters, thereby negating the influence of polls showing that Warren might lose to President Trump. And so far, those who don’t want those policies lack a platform to counter to it.

None of the other contenders have posed their own vision as a strong alternative to the progressive vision. They have tried to run as progressive-lite, backing every progressive goal but with less fervor or at less cost and smaller scope. That concedes the essential argument about the source of the country’s problems and the possible solutions to their progressive adversaries. You can’t rally voters to your side if you don’t give them a reason to rally.

Establishment Democrats have long thought they could keep control of their party by nodding to the left but governing from the center. But that’s not likely to work in an environment where the left wants to seize control, not merely be acknowledged. Today’s young progressive activists have no memories of the McGovern disaster, but they do recall how Clintonian incrementalism led to George W. Bush and Donald Trump. Beating back Warren and her followers will require confrontation of the sort Democrats have largely avoided since the intra-party wars of the late 1960s and early 1970s.

That can be done by the existing field of candidates. Biden is probably a more effective spokesperson for traditional Democratic Party values than either Bloomberg, who was a Republican or an independent as mayor, or Patrick. Sen. Amy Klobuchar (Minn.) could also be an effective spokesperson if she can overcome her Minnesota Niceness and channel happy warrior Hubert Humphrey’s prairie populism. Either will have to take the challenge head on and say in public what many Democrats say in private: democratic socialism won’t work and doesn’t represent our values.

Democrats who want to avoid this fight are simply ostriches hiding their heads in the sand. Progressives aren’t just coming for Trump, but for moderates, too. If the party’s centrists want to keep their heads, they will have to use their wits and fight back, just not with vanity campaigns that come too late.

Read more:

Jonathan Capehart: Why Bloomberg won’t be the Democratic nominee

E.J. Dionne Jr.: Democrats have put their differences above beating Trump. Bloomberg is a symptom not a cure.

Jennifer Rubin: Five better uses of Michael Bloomberg’s money

Paul Waldman: Michael Bloomberg faces a major ideological challenge

Karen Tumulty: Bloomberg has a narrow path to winning. But he’ll sure get under Trump’s skin.