Complex sentence: On December 6, when media sources confirmed that Cochran would run for re-election, McDaniel became Cochran's first primary opponent since 1996, when Cochran won with 95% of the vote.
Split into simpler sentences: On December 6, media sources confirmed that Cochran would run for re-election. McDaniel was Cochran's first primary opponent since 1996, when Cochran won with 95% of the vote.