Congressman Beto O'Rourke, a Democrat running for the U.S. Senate, has released a new piece of campaign merchandise, responding to a criticism by his Republican opponent. This month, Senator Ted Cruz, a Republican seeking re-election to Texas' U.S. Senate seat, released a campaign ad attacking O'Rourke - whose birth name is Robert Francis O'Rourke - for using the nickname "Beto." The attack came in the form of a radio commercial by Cruz's campaign set to the tune of Alabama's "If You're Gonna Play in Texas," charging that O'Rourke also wants open borders and to seize Texans' guns. O'Rourke responded to the nickname criticism by releasing a photo showing him wearing a shirt with the word "Beto" on the front when he was a toddler. O'Rourke's campaign also released a version of the shirt in his campaign store for supporters to purchase. The El Paso Democrat will square off with Cruz in November. Nominees for the Libertarian and Green Parties will also be announced in the coming weeks.