WATCH: History of annual presidential speech
Presidents typically invite to the State of the Union address guests who highlight various policy priorities or who have been impacted by war. Tonight, President Donald Trump's guests include an African-American welder from Ohio who became a first-time homeowner in 2017, the parents of two teenage girls killed by MS-13 gang members, and the first blind double amputee to reenlist in the Marines.
Trump isn't the only one bringing guests to the State of the Union. Several Democratic lawmakers have invited immigrants, including some who are undocumented and face possible deportation. One Arizona congressman isn't OK with it, and has asked Capitol Police to consider checking the IDs of all attendees and "arresting any illegal aliens in attendance."
Other things to keep an eye on in the crowd: Many female Democratic lawmakers are wearing black to show support for the #MeToo movement against sexual harassment (at least 19 women have accused Trump of sexual misconduct; he denies the allegations). At least five Democratic lawmakers are boycotting the address.