Deep divisions between centrist Democrats and progressive members of the party nearly sunk an infrastructure bill that’s a key part of President Joe Biden’s agenda. And that intra-Democratic chasm is on vivid display in many 2022 Democratic primaries, including for an open Pennsylvania Senate seat.

The seat is a linchpin in Democrats’ efforts to broaden their razor-thin majority in the 50-50 chamber, which they hold due to Vice President Kamala Harris’s tiebreaking vote. Republican Sen. Pat Toomey is leaving the seat open after holding it for 12 years. Rep. Conor Lamb is presenting himself to voters in the Pennsylvania Democratic primary, and in the November 2022 general election if that goes well, as a relatively centrist alternative to extremes in both parties.