The Electoral College affects presidential elections by creating a system where states allocate votes based on the popular vote within each state. This means that candidates must focus on winning key swing states, rather than simply garnering the majority of the national popular vote. As a result, this system can lead to outcomes where a candidate wins the presidency without winning the popular vote, raising questions about democratic legitimacy and representation. The structure also encourages a binary political landscape, often marginalizing third-party candidates and affecting campaign strategies.