Democrats rode a wave of firsts on Tuesday, becoming in Vermont the first major party to nominate an openly transgender person for governor, while potentially picking the first African-American Democrat to serve in the House from Connecticut.

They were among the big highlights from a round of primaries across Minnesota, Wisconsin, Connecticut and Vermont that also featured state Rep. Ilhan Omar, a Muslim woman who emerged as the Democratic nominee for a House seat currently held by another Muslim, Rep. Keith Ellison Keith Maurice EllisonOfficers in George Floyd's death appear in court, motion for separate trials Ex-Minneapolis officer involved in Floyd death asks judge to dismiss murder charge Over 50 current, former law enforcement professionals sign letter urging Congress to decriminalize marijuana MORE (D-Minn.).

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Meanwhile, establishment candidates prevailed in Senate races in Wisconsin, where state Sen. Leah Vukmir, who won the endorsement of the state GOP earlier this year, emerged victorious over Marine Corps veteran Kevin Nicholson, a former Democrat who cast himself as a political outsider.

Likewise, in Minnesota, Sen. Tina Smith Tina Flint SmithThe Hill's Campaign Report: Trump faces backlash after not committing to peaceful transition of power Credit union group to spend million on Senate, House races Health officials tell public to trust in science MORE (D) overcame a challenge from Richard Painter, a former ethics lawyer for President George W. Bush, in one of the state’s Democratic Senate primaries.

Here are the five takeaways from Tuesday’s primaries:

The establishment flexes its muscle

It was a good night for the establishment, especially in Wisconsin’s GOP primary for Senate.

Vukmir, who won the Wisconsin Republican Party’s endorsement in May, edged out first-time candidate Nicholson in the state’s GOP Senate primary, setting her up to challenge incumbent Sen. Tammy Baldwin Tammy Suzanne BaldwinSenators introduce bipartisan bill to mandate digital apps disclose country of origin Keep teachers in the classroom Cher raised million for Biden campaign at LGBTQ-themed fundraiser MORE (D) in November.

Vukmir won the support of prominent Republicans and conservatives groups, including House Speaker Paul Ryan Paul Davis RyanKenosha will be a good bellwether in 2020 At indoor rally, Pence says election runs through Wisconsin Juan Williams: Breaking down the debates MORE (R-Wis.), former White House chief of staff and Wisconsin GOP Chairman Reince Priebus Reinhold (Reince) Richard PriebusLeaked audio shows Trump touted low Black voter turnout in 2016: report Meadows joins White House facing reelection challenges Trump names Mark Meadows as new chief of staff MORE, and the National Rifle Association.

Nicholson sought to cast Vukmir, a longtime player in Wisconsin Republican politics and an ally of Gov. Scott Walker (R), as a political insider. But that line of attack failed to work with Wisconsin's GOP primary voters.

That's not to say that President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE was absent from the race. Though he didn't endorse anybody, Vukmir often name-checked Trump’s policy proposals on the campaign trail, expressing her support for his long-promised border wall and pledging to help “drain the swamp” in Washington.

Her support for Trump was meant to inoculate herself from charges from Nicholson that she had been insufficiently loyal to the president.

Vukmir had made critical comments of Trump in the past and initially supported Walker during the 2016 GOP presidential primaries, before backing Sen. Marco Rubio Marco Antonio RubioGOP lawmakers distance themselves from Trump comments on transfer of power McConnell pushes back on Trump: 'There will be an orderly transition' Graham vows GOP will accept election results after Trump comments MORE (R-Fla.).

But as a former Democrat, Nicholson was also vulnerable in a Republican primary, and he ultimately failed to make much of his Trump attacks against Vukmir.

The establishment also held strong in a couple of Minnesota primaries.

Smith, who was appointed to the seat after Sen. Al Franken Alan (Al) Stuart FrankenGOP Senate candidate says Trump, Republicans will surprise in Minnesota Peterson faces fight of his career in deep-red Minnesota district Getting tight — the psychology of cancel culture MORE’s resignation, cruised to victory over Painter. Smith, the former lieutenant governor, has deep ties to Minnesota’s Democratic-Farmer-Labor Party, which endorsed her in the special election.

One glaring exception was in Minnesota’s governor race, where former Gov. Tim Pawlenty failed to make a comeback bid. Hennepin County Commissioner Jeff Johnson won the Republican primary instead, after closely aligning himself with Trump.

Democrats make history

Democrats have been making history this cycle as more female, LGBT and minority candidates run for Congress — and win.

In Vermont, Democrats elected the first transgender gubernatorial nominee of a major political party after Christine Hallquist, a first-time candidate and the former CEO of the state’s electricity co-op, emerged as the winner of the primary.

She now faces Republican Gov. Phil Scott in November, though it’ll be an uphill climb for Democrats to take back the governor’s mansion. Vermont may be a blue state, and one that Democratic presidential nominee Hillary Clinton Hillary Diane Rodham ClintonFox News poll: Biden ahead of Trump in Nevada, Pennsylvania and Ohio Trump, Biden court Black business owners in final election sprint The power of incumbency: How Trump is using the Oval Office to win reelection MORE easily won in 2016, but Scott remains popular, winning his first term by 8 points that same year.

And in Minnesota’s 5th District, Omar won in a crowded Democratic primary, and she’ll likely be among the first Muslim women elected to Congress along with former state Rep. Rashida Tlaib, who won her Michigan Democratic primary earlier this month.

Omar ran in the race to replace Ellison, who in 2006 was the first Muslim elected to Congress. A Somali-American, she was endorsed by Alexandria Ocasio-Cortez, a democratic socialist who defeated a longtime incumbent in a New York House primary.

And in the race to replace Rep. Elizabeth Esty (D-Conn.), Democrat Jahana Hayes, the 2016 Teacher of the Year, would be the first African-American Democrat elected to Congress from Connecticut — if she wins the general election in November.

'Ironstache' wins, but faces complicated path in race for Ryan's seat

Ironworker Randy Bryce may have secured the Democratic nomination to replace Ryan, the retiring House Speaker, in the southeast Wisconsin district, but it’s not likely to be smooth sailing for the candidate dubbed “Ironstache” as he heads into the general election.

The mustachioed 53-year-old garnered a reputation as a rising Democratic star after he announced his candidacy last summer in an emotional video about how his mother was struggling to afford vital drugs, which quickly went viral.

But Bryce faced a tougher-than-expected challenge from Janesville school board member Cathy Myers after being hit by a series of negative headlines regarding his past arrests for marijuana possession and driving under the influence, as well as the revelation that he failed to pay child support until after he declared his House bid.

Those revelations are sure to fuel Republican attacks ahead of November, complicating his campaign fight against Republican Bryan Steil, who also secured his party’s nomination on Tuesday.

Steil is a former aide to Ryan and received the endorsement of the outgoing Speaker. What’s more, the Cook Political Report rates the district as "leaning Republican," meaning Bryce and the Democrats are almost certain to face a tough path in flipping Wisconsin’s 1st District.

Will abuse allegations rock Ellison's bid for AG in November?

Ellison easily won the Democratic primary for Minnesota attorney general, but it remains to be seen how his campaign will be affected going forward by recent domestic abuse allegations.

Ellison won 51 percent of the vote against four other Democrats in the open-seat race. Ellison had been considered the front-runner since he announced his candidacy in June.

But in recent days Ellison has faced abuse allegations after the son of his ex-girlfriend posted on Facebook that he watched a video where the congressman allegedly dragged his mother off a bed and shouted profanities at her.

The ex-girlfriend, Karen Monahan, backed up her son’s account. But Ellison denies those allegations, saying that the video referenced doesn’t exist.

It’s still unclear how, or if, the allegations will roil Ellison’s campaign going forward. But they’re being taken seriously. The Democratic National Committee said on Tuesday that it is “reviewing” the abuse allegations levied at Ellison, who serves as the committee's vice chairman.

Ellison will face former state Rep. Doug Wardlow in November.

'Medicare for all' winning among Democrats

"Medicare for all" may not be fading from the headlines any time soon after a number of Democrats won their respective primaries after campaigning heavily on that health-care message

Few candidates did it as poignantly as Bryce, who made single-payer health care a critical part of his campaign messaging, including in his viral campaign announcement video featuring his mother. He was endorsed by Sen. Bernie Sanders Bernie SandersThe Hill's Campaign Report: Trump faces backlash after not committing to peaceful transition of power Bernie Sanders: 'This is an election between Donald Trump and democracy' The Hill's 12:30 Report: Trump stokes fears over November election outcome MORE (I-Vt.), who has championed Medicare for all legislation in the Senate.

Meanwhile, in Minnesota, Omar ran a progressive platform that includes a single-payer system among other progressive issues. And in Connecticut, Hayes also backs Medicare for all, as does Hallquist in Vermont.

Republicans have already indicated that they plan to weaponize Medicare for all, arguing that it’ll spook more moderate voters in competitive seats. But Democrats who ran on this platform will ensure that it’ll likely remain a campaign issue — provided they continue to talk about it frequently in a general election.