Former President Donald Trump called for unity and resilience Sunday after an attempt on his life added fresh uncertainty to an already tumultuous presidential campaign. Setting aside stark political differences during a delicate stretch of the race, President Joe Biden used a prime-time address to condemn the violence and implore Americans that "we can’t, we must not go down” the road of political violence. "The attempt to assassinate Trump has really heightened that tension, the stakes of this campaign," University of Denver international studies professor Fritz Mayer said. Mayer said the shooting could be tied to the contention in the country during the current election cycle. "It's a moment where we are when we don't talk about 'we,' it's 'us vs. them,'" Mayer said. "It's really sharply divided, and to a point where it isn't in some way surprising that this kind of thing happened, and surely there would be those who would target Biden if they could." Mayer said there will be continued conversations around the attempted assassination as the presidential race continues. Read more: https://www.9news.com/article/news/nation-world/du-international-studies-dean-on-trump-shooting/73-b3d7ea47-603e-439a-9420-f3760aa79f94 ----- More local videos here: https://youtube.com/@9news Subscribe to NEXT: https://youtube.com/@Nexton9NEWS Stay connected: 9NEWS Website: https://www.9news.com/ Facebook: https://www.facebook.com/ilike9news Twitter: https://twitter.com/9NEWS Instagram: https://www.instagram.com/9newsdenver/ Download the 9NEWS App: https://www.9news.com/appredirect/ Sign up for the 9NEWSLETTER: https://www.9news.com/email 9NEWS (KUSA) is located in Denver, Colorado.