Former Deputy President Rigathi Gachagua, alongside leaders including Kalonzo Musyoka and Eugene Wamalwa, campaigned vigorously in Embu County's Mbeere North constituency to support opposition candidate Newton Karish in the November 27, 2025 by-election. The seat became vacant after Geoffrey Ruku's appointment to the Public Service Cabinet, intensifying rivalries between the ruling United Democratic Alliance and the united opposition. Gachagua accused state actors of vote-buying and violence, while conducting morning walks and door-to-door visits, including an unconfirmed stop at Ruku's grandmother's home.
