"Many people here today want to join a union, but you can’t,” SEIU’s Mary Kay Henry says at start.
Sanders has previously called for banning right-to-work, which could not pass a GOP Senate.
The Q ends up being about TPS, but Klobuchar is ready with an immigration reform answer.
But both Klobuchar and O'Rourke ran behind Obama 2012 in some red rural counties, even while beating his MN/TX margin from that year.
Castro had announced his intention to recognize a union before Sanders did, but the Sanders campaign organized first.