The synchronized crackup of America’s major political parties proceeds rather briskly.

Republicans hold on for dear life, day by dizzying day, waiting to see what will be left of their party (or right of it, for that matter) once the winds of Superstorm Donald finally die away.

But chaotic crosscurrents are also blowing Democrats into uncharted regions — and might be pulling them apart if their loathing for President Trump weren’t holding them together.

Democratic fractures were on vivid display during a midsummer round of Star Tribune Editorial Board endorsement interviews in advance of Minnesota’s Aug. 14 primary. The DFL’s party-endorsed candidates for four major offices — governor, U.S. senator, state attorney general and the U.S. House seat representing Minneapolis and its environs — all face spirited challenges.

And in different ways each contest lays bare the deepening rift between what remains of moderates in Democratic ranks and the ultraprogressive champions of what can only be called a great leap leftward.

Setting aside the president’s inimitably untraditional style, Trumpist policies can be understood as a kind of return to GOP roots, tapping deep wells of American sentiment and embracing principles cherished especially by Republicans of the late 19th and early 20th centuries. Protectionism, nativism and isolationism were pillars of conservative thinking for decades on end before World War II, until free trade and anti-communist internationalism became GOP norms. It’s the ideology of Calvin Coolidge and Robert Taft, only without their prudence and good manners.

The Democratic unraveling, like most things Democratic, is more complicated, but also sports retro elements. Icons of the new order such as Vermont Sen. Bernie Sanders and New York’s superstar congressional hopeful Alexandria Ocasio-Cortez proudly embrace the label “socialist.” Many other progressives embrace, or at least are under pressure to embrace, an eye-popping agenda of gigantic new entitlement programs and economic interventions (single-payer health care, free college and job guarantees for all, lofty nationwide minimum wages and other workplace regulations, clean energy mandates, etc., etc.). Full legalization of marijuana has become mere Democratic orthodoxy.

It all resembles the unapologetically soaring ambitions for visionary government that fueled the New Deal of the 1930s and the Great Society of the 1960s.

Some of those ambitions may be pursued in court, via lawsuits brought by an increasingly adventurous cadre of state attorneys general around the country. Five DFLers are running in Minnesota’s AG primary, following incumbent Lori Swanson’s stepping aside (only to later enter the race for governor) after she failed to be endorsed for re-election on the first ballot at the DFL state convention.

Many suspect Swanson’s change of plans may have been well planned, but Swanson complains of an extremist atmosphere at the convention — of having been asked to pledge support for disarming police.

Three DFL AG candidates — former Commerce Commissioner Mike Rothman, state Rep. Debra Hilstrom and former Washington and Ramsey County Attorney Tom Foley — take an essentially traditional view of the office as the state’s chief lawyer and enforcer of consumer protection law. They express at least some lawyerly caution about more adventurous legal action to change public policy.

But the front-runner to take Swanson’s place on the ballot is Fifth District congressman Keith Ellison, a rising national star of fearless progressivism. Along with Matt Pelikan, the candidate the DFL convention endorsed to replace Swanson, Ellison sees the AG post as an opportunity to pursue a broad progressive economic agenda.

Perhaps testifying to the role attorney general seats play in national progressive strategy, Sanders was headliner at a campaign rally for Ellison last month, capturing the confidence and methodology of the new movement when he promised (almost warned): “The way the political revolution works is that ideas that yesterday seemed radical today seem mainstream.”

For governor, the DFL endorsed an accomplished and mild-mannered but passionately liberal state representative from St. Paul, Erin Murphy, who envisions among other things a full single-payer model for health care and free college tuition for students whose family incomes fall below … $150,000. She is challenged in the primary by Swanson and by U.S. Rep. Tim Walz from southern Minnesota’s rural First District. Both are more moderate, centrist Democrats, by today’s standards.

Swanson boasts of cutting spending in the attorney general’s budget. Walz expresses frustration over runaway costs in higher education.

Swanson’s close ties with her mentor, former boss and former subordinate, former Attorney General Mike Hatch, raise questions in many quarters about his influence should she become governor, especially among critics who say both have earned reputations as controlling intriguers. Asked in her interview whether she anticipates a role for Hatch in a Swanson administration, Swanson answered that she has made no staffing plans.

Walz, meanwhile, tellingly points out that rural Democrats like him are a vanishing breed.

In the race to replace Ellison in Congress, the DFL center is yet again challenging the new power structure. Running in the primary are two veteran Minneapolis lawmakers, former state House Speaker Margaret Anderson Kelliher and state Sen. Patricia Torres Ray, both solid if pragmatic liberals.

But the endorsed hopeful they are challenging, first-term state Rep. Ilhan Omar, is the youthful immigrant face of the anti-Trump resistance, the embodiment of progressive calls to abolish Immigration and Customs Enforcement (ICE) and “re-imagine” immigration and criminal justice policies — and indeed of the whole agenda of “ideas that yesterday seemed radical.”

Yet nothing may illustrate the fragility of DFL unity like the party’s nasty public spat with Richard Painter, the sharp-tongued ethics lawyer, former Republican and self-styled Trump nemesis who is running for nomination to Al Franken’s former U.S. Senate seat. Incumbent Tina Smith, appointed to the job last winter, is a consummate party insider, the able former chief of staff for Gov. Mark Dayton and Minneapolis Mayor R.T. Rybak. Her impeccable establishment liberal credentials include her background as an executive at Planned Parenthood.

Painter is a product of the disruptive times, calling for hearings to weigh Trump’s impeachment and denouncing proposed sulfide mining on the Iron Range, urging Rangers to get over their “obsession with mining.” An uncharacteristic stance, shall we say, for a statewide DFL candidate.

Last week, according to news reports, DFL Party Chair Ken Martin publicly blasted Painter as “‘a wolf in sheep’s clothing’ who refuses to say he is a Democrat,” and Painter agreed that he “won’t swear allegiance to a party.”

Undisciplined candidates. Uncompromising factions. Uncomfortable moderates. Our major parties may be poles apart today, but they have some things in common.

D.J. Tice is at Doug.Tice@startribune.com.