Thomas joined the Maricopa County Attorney's Office as a Deputy County Attorney in 2003, then ran successfully for Maricopa County Attorney in 2004, having campaigned for state-based laws and initiatives against illegal immigration, pledging to pursue "fetal homicide" cases, and opposing same-sex marriage.
Thomas became a Deputy County Attorney in the Maricopa County Attorney's Office in 2003, then won an election to become Maricopa County Attorney in 2004. He campaigned on anti-immigration measures, vowed to prosecute 'fetal homicide' cases, and opposed same-sex marriage.