CHICAGO The biggest X-factor for any presidential candidate is a simple question consultants like to ask: Can you picture this person as president the kind of person with the dignity and seriousness needed to run the largest military on earth and handle difficult conversations with foreign leaders while sitting at the Resolute Desk?

Call it the 3 a.m. phone call test, as Hillary Clinton put it in a 2008 campaign ad , describing the qualities needed to have confidence in a leaders ability to handle a crisis under pressure.

On Thursday night, political leaders, military veterans and law enforcement officials came together to portray Vice President Kamala Harris as a proven leader capable of serving as commander in chief on day one.