California Senate leader Kevin de León will announce his bid for the U.S. Senate today, challenging fellow Democrat and incumbent Dianne Feinstein who has held the seat since 1992, per the LA Times.

The backdrop: Feinstein "has faced heated criticism in recent months from liberal critics who have said her measured approach is no longer representative of a state that has become home to "the resistance" to President Trump and his policies," the LA Times reports. But De León faces a tough fight. Feinstein is a respected veteran of the Democratic party and wealthy enough to fund her own campaign.