California’s Senate race was expected to be a three-way Democratic prizefight, but the possibility of a record-low turnout is elevating the chances of Republican Steve Garvey, a former baseball star, and could derail the congressional careers of two prominent progressives.

In a year headlined by a likely presidential rematch that many Americans are dreading, California voters thus far have been sluggish to return mail-in ballots that were sent to 22 million homes earlier this month. The relative trickle of ballots has tended to come from older, white, conservative-leaning homeowners, a sweet spot for Republicans such as Garvey, a one-time National League MVP who played for the Los Angeles Dodgers and the San Diego Padres.

For months, Rep. Adam Schiff has had the fundraising and polling edge in a crowded Democratic field. Garvey's ascent has imperiled the political prospects of Reps. Barbara Lee and Katie Porter.