The ascendance of Democratic pragmatists amid the party’s leftward lurch faces a key 2022 test with Rep. Conor Lamb’s entrance into the Pennsylvania Senate race.

Lamb’s main competition for the Democratic nomination is John Fetterman. The lieutenant governor embodies the progressive populism, and reflects the ideological liberalism, of a Democratic base that has drifted further to the left in recent years and grown more dominant over party affairs. Montgomery County Commissioner Val Arkoosh and state legislator Malcolm Kenyatta are two more of the handful of liberal Senate contenders who could block Lamb from the nomination.