Final answer:
Abraham Lincoln debated Stephen Douglas while running for Senator of Illinois in 1858. The debates gained national attention and raised Lincoln's profile.
Step-by-step explanation:
Abraham Lincoln debated Stephen Douglas while he was running for Senator of Illinois in 1858. The two engaged in seven debates on the central issue of slavery and its expansion, which gained national attention and raised Lincoln's profile. Although Douglas won the seat, the debates propelled Lincoln into the national political spotlight.