Politico readers learned two interesting things this week.

One: A prominent political scientist is making a novel argument that elections are won not by persuading swing-voting independents but by turning out the greatest number of people already inclined to support your side. This new reality, she argues, should prompt parties to back candidates who generate enthusiasm among those who might otherwise sit home or cast a protest vote, not moderates who might be able to persuade independent voters to switch parties.

Two: Democrats are furious that a shady conservative PAC has begun spending money to boost the candidacy of a liberal candidate in the Democratic primary for North Carolina’s upcoming Senate election over the more moderate front-runner.

The political scientist is Rachel Bitecofer. You don’t have to accept her claims (which involve highly specific election forecasting) in their entirety to note that they seem at least broadly true of recent elections and explain events, such as the election of Donald Trump, that caught more traditional political scientists off guard. Hillary Clinton was brought low, in this telling, not because too many Democrats defected to Trump, but because too many of them stayed home (or had their votes suppressed) or voted third-party. The related concept of “negative partisanship”—that opposition to the other party, not loyalty to your own candidate, drives the voting of many Americans—also helps explain both why so many traditional Republicans voted for Trump and why Democrats were able to make huge gains in the 2018 midterms.

All of which brings us back to North Carolina, where Democrats are growing increasingly anxious that a more liberal candidate might edge out the one they’ve blessed.