She continued to be critical of the state of American politics. In September 2019, she declaimed the Republican Party as "excluding people for the wrong reasons" and said it was no longer "the party that my husband and I belonged to." In contrast, with the 2020 United States presidential election underway, she praised Democratic presidential front-runner Joe Biden and his wife Jill Biden, saying that they were good friends to her and that "Joe has been a remarkable source of inspiration, kindness and just a shoulder throughout all of this." In June 2020, McCain stated that she would not endorse Donald Trump's re-election campaign. While not explicitly endorsing Biden at the time, McCain spoke in a video segment shown at the August 2020 Democratic National Convention about the friendship between her late husband and Biden. On September 22, McCain gave her full endorsement to Biden's presidential candidacy. McCain's endorsement, and the bad relationship between Trump and her late husband, has been given as one of a number of reasons why Biden was able to narrowly win the 2020 United States presidential election in Arizona. In doing so Biden became the first Democratic presidential candidate since 1996, and only the second since 1948, to do so.