The presidential race is now entering a critical phase. With early voting beginning in many states and Election Day only seven weeks away, any misstep by either Kamala Harris or Donald Trump will be difficult to overcome. Both campaigns and their aligned groups will likely become more hard-edged in their efforts to bolster their support, deflate opponents’ claims, and rally undecided voters.

This election, like many in the past, has been tightly contested. Harris and Trump are both neck and neck in the national popular vote and most polls show them tied or ahead in the states that will decide the winner of the Electoral College. The current debates are an important opportunity for both candidates to amplify their message and shape public perceptions of their campaign.

In the past, debates have generally had relatively small impacts on the outcome of a presidential race. This year, however, could be different. In June, President Biden had a disastrous performance in a nationally televised debate against Trump. His stumbling, meandering answers and raspy voice were widely perceived to have diminished his credibility as a candidate. Biden subsequently dropped out of the race and endorsed Harris.

The Electoral College system rewards states for their traditional leanings toward one party or the other, which encourages candidates to spend exponentially more time and money in a few “swing” states where no candidate has a clear advantage. Currently, no candidate has a secure lead of more than about five points in any state and none is close to securing the 270 electoral votes needed for a win.