The surprise victories of Alexandria Ocasio-Cortez in New York’s 14th Congressional District and Ayanna Pressley in Massachusetts’s Seventh Congressional District were important because both candidates were relatively young women of color who reflected the changes in their district. Both defeated white men in majority-minority districts. But these men were liberal, especially Mike Capuano in Massachusetts. The two women are favored to win in November, and in Congress , their votes are not likely to differ significantly from the votes of the members they replace, so they will not change the distribution of votes in the House Democratic Caucus.

Second, the most successful endorsement group in the 2018 primaries was not Our Revolution or any of the other new progressive political action groups — it was that most staid of all organizations, the Democratic Congressional Campaign Committee, which won 39 of the 41 races in which it endorsed a candidate. By focusing on candidates who “fit” the district and had deep roots there, such as Jason Crow in Colorado and Linda Coleman in North Carolina, the congressional committee was looking at more than ideology. It was looking for candidates who could win.

Third, progressive candidates brought both a new energy and a new issue to the table this year. A recent Pew Research Center report shows that Democratic turnout in the congressional primaries was up substantially this cycle — a 56 percent increase over the 2014 midterm elections. This is most likely a function of the large jump in contested Democratic primaries and the energy on the left.

The new issue was Medicare for All. In our review of the congressional candidates, this was endorsed much more often by progressive candidates than by establishment ones. But this is not as divisive an issue as some would make it out to be. Democratic Party platforms have called for universal health care for decades.

Buy-in to Medicare for those over 55 years old was considered by the Democratic Congress in 2009 and lost narrowly. Medicare for All will be debated if the Democrats return to power.

But in the meantime, it is not the kind of idea that will cause a civil war inside the Democratic caucus. As we go into the November elections, the notion that the Democratic Party has been captured by the extreme left simply doesn’t hold water.

Elaine Kamarck is a senior fellow at the Brookings Institution and the author of “Primary Politics: Everything You Need to Know About How America Nominates Its Presidential Candidates.”

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