President Biden and former president Donald Trump agreed Wednesday to a June 27 debate on CNN and a Sept. 10 debate broadcast by ABC News, bypassing the decades-old tradition of three fall meetings organized by the bipartisan Commission on Presidential Debates.

The decisions by the major-party candidates to take control of the once independent debate planning process upended the timeline that has defined presidential contests for decades, adding unpredictability to an already close race. The two debates will happen much earlier than normal, which could decrease their impact on the election or awaken voters who have not yet tuned in.