But many senior Republicans worry that Walker will inevitably stumble against Warnock, who has become a fundraising powerhouse and national figure since defeating GOP incumbent Kelly Loeffler in January to become the first Black U.S. senator in Georgia history.

Along with his long-standing Texas residency, Walker has a history of violent and erratic behavior, some of which he’s attributed to his struggles with mental illness. His stance on major policies, along with his ability to court grassroots voters and donors, is a mystery. He’s skipped key political events that most prospective contenders in Georgia attend.

Still, his flirtation with a run froze out other prominent Republicans, including U.S. Rep. Buddy Carter, who repeatedly said he wouldn’t run if Walker was competing. But three other contenders entered the race months ago, and they could immediately test Walker’s popularity with Republican voters.