There was a primary in Massachusetts on Tuesday, but nobody was really paying attention to it. In Massachusetts’ 7th District, there was a primary held on the Democratic side where, for the second time this year, a progressive candidate running on the Bernie Sanders platform of Democratic-Socialism has unseated a sitting incumbent. Democrat Mike Capuano had represented the district since 2013, but his tenure has come to an end at the hands of the new wave of progressivism in the Democratic Party. The challenger, Ayanna Pressley, had the backing of Alexnadria Ocasio Cortez, the first socialist-leaning Democrat to pull a big upset this year against an entrenched Democratic incumbent in New York City.

Coverage of the Massachusets primary upset comes from The Daily Beast:

Ayanna Pressley, the 44-year-old Boston City Councilor, triumphed over 20-year incumbent Rep. Michael Capuano (D-MA) by a double-digit margin. It was the primary season’s second stunning ousting of a long-term lawmaker by a female progressive challenger and another indicator that the liberal base is hungering for something new in their representation.

Massachusetts’ 7th District, the only majority-minority district in the liberal state, once sent President John F. Kennedy to Congress and was viewed prior to Tuesday’s contest as the kind of area that was ripe for a shakeup. Coupled with Pressley’s compelling candidacy, a late primary the day after Labor Day, and district lines that were redrawn in 2011, Capuano was clearly vulnerable.

Just over an hour after polls closed at 8, there was chatter among those at Capuano’s victory party that the congressman was preparing to concede. Minutes later he did so, long before the race had been officially called

“I’m sorry it didn’t work out, but this is life, and this is OK,” Capuano said around 9:15. “America’s going to be OK. Ayanna Pressley is going to be a good congresswoman, and I will tell you that Massachusetts will be well served.”

Pressley even received a congratulatory tweet from Cortez:

In the grand scheme of the 2018 midterms, these primary upsets are simply replacing incumbent Democrats with new Democrats, but what does it mean for the general election in November? Clearly the Democratic base is tilting to the left, and some establishment incumbents are paying the price if they aren’t catering to the tilt. This political shift is creating some situations where Democrats have put up very liberal candidates in areas where they may have a hard time winning against more moderate or centrist Republicans.

As NPR notes, there is a streak for women of color winning primaries this season, and the numbers are starting to mount:

Pressley is poised to become the first African-American woman to represent Massachusetts in the state’s congressional history.

“It’s not enough for Democrats to be back in power,” she said at her election night celebration. “It matters who those Democrats are.”

Pressley’s victory is indicative of the the broader success of female Democrats this election cycle. She joins a number of other black women who’ve won their primaries this year, including Stacey Abrams, who’s running for governor in Georgia, Lauren Underwood, running for a congressional seat in Illinois, and Jahana Hayes, who’s also running for a seat in Congress from Connecticut.

The Democratic Party has referred to African-American women as the backbone of the party, but in recent years, some black organizers have expressed frustration that the party has not invested in recruiting black candidates. Pressley’s victory is a sign that organizers and activists are no longer willing to wait for the party’s blessing.

It’s also a sign that issues of representation rather than ideology are motivating voters in Democratic primaries.

If Donald Trump was a paradigm shift in the Republican Party, we could be seeing the parallel shift within the Democratic Party right now which is a lurch to the left, and the blossoming of freshman minority candidates. In fact, you could compare this time to the Tea Party uprising in 2010 where many new, non-politicians came out of the woodwork to run for Congress, essentially against President Obama’s policies, on the Republican side. This created a new wave of political outsiders unseating GOP incumbents and perhaps a similar trend is taking place on the Democratic side in response to President Trump.

The good news for Pressley is that there is no Republican running in Massachusetts’ 7th district, the seat will be hers in an uncontested election. She’ll still have to win in November, but there will be no real opposition on the ballot against her. Winning the primary was the equivalent of winning the general.