Representative Mike Collins, who lags Senator Jon Ossoff in public polls, hit his opponent harder in a second and final debate on Tuesday.

Candidates in three of the races that could determine control of the Senate engaged in bitter and personal attacks.

Candidates in three of the races that could determine control of the Senate engaged in bitter and personal attacks.

Senator Jon Ossoff, a Democrat, called his Republican opponent, Representative Mike Collins, a bigot. Mr. Collins called the incumbent a radical “trust-fund kid.”

Each debate will be held in a TV studio without a live audience.