Bernie Sanders is sputtering.

Two years after his defeat in the 2016 presidential primary, the Vermont senator has amassed a growing string of losses in races in which he has intervened. Beginning last year, Sanders-backed candidates faltered in an Omaha mayoral race and a nationally watched House race in Montana.

Then came Representative Tom Perriello’s loss in Virginia’s gubernatorial primary, and in June, the drubbing in Iowa of Pete D’Alessandro, a top adviser to Sanders during his 2016 Iowa caucus campaign. Cathy Glasson, endorsed by Sanders’ successor group, Our Revolution, fell short in Iowa’s gubernatorial primary, as did Peter Jacob and Jim Keady in two New Jersey House races. Dennis Kucinich lost in Ohio.

Tuesday night brought Sanders and his army their latest blow, with a pair of high-profile losses in Michigan and Kansas.

Emerging from the 2016 election, Sanders’ political prospects appeared to hinge on his ability to sway the Democratic Party’s left flank. And Sanders’ campaign is widely considered instrumental in a recent surge in small donors and young people registering to vote, and in the elevation of issues such as student debt and universal health care.

Sanders supporters credit his 2016 campaign with driving support for progressive policies on health care and student loan debt into the Democratic Party’s mainstream.

Yet in high-profile races across the country, Sanders-backed candidates continue to falter at the ballot box. The losses suggest organizational weaknesses that could hamper Sanders if he runs for president again in 2020 — even as a diaspora of Sanders-aligned candidates continues to test his appeal in the midterm elections.

The Tuesday elections offered the first significant test of Sanders’ ability to influence a Democratic primary since June. And this time, he had high-profile help from Alexandria Ocasio-Cortez, an instant sensation for progressive Democrats since her stunning upset — notably, without the endorsement of Sanders — of Representative Joe Crowley in New York.

In a crowded Democratic primary in Kansas, former Sanders campaign staffer Brent Welder said before results were finalized on Tuesday night that his “message of bold progressive values and running an uncorrupted campaign that does not take corporate PAC money is resonating with people across Kansas, across the district and across the country.”

Echoing Sanders’ rhetoric from the 2016 presidential campaign, he told supporters in his suburban Kansas City district, “We are going to prove that we can and we will succeed [in] sending a congressman to Washington who is not corrupted and who will stand up to Wall Street and the giant corporations and the billionaires that are buying our politicians.”

But hours later, the race was called for Welder’s opponent Sharice Davids, an attorney who will take on Representative Kevin Yoder (R-Kan.) in November.

Sanders did even worse in Michigan, where he and Ocasio-Cortez campaigned aggressively for Abdul El-Sayed, who was trampled by more than 20 percentage points in the Democratic primary for governor. Sanders rallied supporters in Detroit over the weekend. El-Sayed, a 33-year-old physician, was seeking to become the first Muslim governor in the nation.

El-Sayed lost to former state Senator Gretchen Whitmer, the favorite of the Democratic establishment.

Sanders supporters credit his 2016 campaign with driving support for progressive policies on health care and student loan debt, among other issues, into the Democratic Party’s mainstream.

Down-ticket, however, candidates aligned with Sanders or Our Revolution have fared only marginally better, including on Tuesday.

Nationwide, of 37 Our Revolution-endorsed candidates who worked for Sanders or volunteered on his campaign, all but nine entered Tuesday’s primaries still in the running or having already won their elections. Three of them, including Welder, lost Tuesday, and a state Senate candidate in Michigan was running behind. But three Our Revolution-backed candidates who ran unopposed in state legislative races Tuesday will appear on ballots in Washington, Kansas and Missouri in November.

Sanders also campaigned for James Thompson, who won his primary in a less competitive Kansas House district Tuesday. And Our Revolution-endorsed candidates have already won local contests elsewhere.

Earlier this year, Our Revolution-backed Brandon Johnson toppled an incumbent Democrat in the primary in a Cook County commissioner’s race, while Kristin Seale, a delegate for Sanders at the 2016 Democratic National Convention, advanced from her primary in a state legislative race in Pennsylvania. Marcus Ferrell, who served as Sanders’ national African-American outreach director in 2016, is running for a state legislative seat in Arizona.

Sanders’ son Levi Sanders is running for Congress in New Hampshire, though without Sanders’ formal endorsement.

And more Sanders-aligned candidates are entering the fray. Michael Ceraso, Sanders’ former California state director and deputy state director in New Hampshire, said Wednesday that he plans to file papers to run for a city council seat in Claremont, California, this week.

Local progressive activism owes as much to an electorate recoiling from President Donald Trump as it does to an embrace of Sanders.

Sanders “raised the bar on the issues,” said Ceraso, who also worked on Barack Obama's 2008 campaign. “I don’t know that it’s the Bernie name that matters. But the remnants of the issues that he talked about certainly matter at the local level. People are talking about these issues.”

Even candidates with unlikely prospects of success point to their campaigns as evidence of Sanders-style enthusiasm spilling over from 2016.

Curtis Wylde, who ran unopposed for a Missouri state legislative seat Tuesday, will advance to face a Republican who defeated him in 2016. Wylde, a professional wrestler and wedding DJ, said he became active in politics only “after hearing Bernie’s call about a political revolution and realizing that regular people needed to get involved in our political system, and needed to try to tip the scales in the way of the regular everyday voter.”

“What it is is that most people don’t realize that Bernie Sanders actually won,” Wylde said.

Noting that some volunteers who telephoned voters for him in 2016 are now running for state and local offices themselves, he said, “What [Sanders] wanted to do was mobilize millions of people to get politically involved, and he achieved that in droves. Change is slow. Progress is slow. But it’s inevitable. So, even if we have some devastating losses, we have to stick at it.”

Matt McLaughlin, who chaired Sanders’ 2016 campaign in Somerville, Massachusetts, and is an alderman there, said a surge in local progressive activism owes as much to an electorate recoiling from President Donald Trump as it does to an embrace of Sanders.

But even as Sanders-backed candidates lose top-tier races, McLaughlin pointed to successes locally as evidence of an effort to rebuild the Democratic Party in a more progressive mold.

“My philosophy — and I think it’s what Bernie was going for — the Republican Party years ago when they couldn’t win elections, they did some soul searching and ran people at the local level,” he said. “Thirty, 40 years later they control every level of government. … That’s what the Democratic Party needs to do. They need to get some fresh faces, go back to their roots and reorganize.”