The Minnesota House began its debate on unionization of home health care workers and child care workers at 2 a.m. Sunday morning.
The debate is expected to last for a while. The Minnesota Senate debated the measure for 17 hours. The House has twice as many members as the Senate.
The measure brought hordes of supporters and opponents to the Capitol, who spent all of Saturday pressing their views.
Backers say the measure would simply let workers vote on whether to join a union.
"It does not create or form a union," said bill sponsor Rep. Michael Nelson, DFL-Brooklyn Park.
Opponents say it would force private workers to unionize.