One of the more closely watched bits of etiquette related to the State of the Union address took place before President Trump began speaking. As he entered the House chamber, Trump shook hands and exchanged greetings with the four members of the Supreme Court in attendance: Chief Justice John Roberts, Amy Coney Barrett, Brett Kavanaugh, and Elena Kagan, reports the AP. The address came days after the court invalidated most of Trump's tariffs, and the president has repeatedly criticized and ridiculed the ruling and the justices who voted against him—particularly Barrett, one of his appointees. Of that group, only Kavanaugh voted in favor of the tariffs.