Supporters and opponents of a unionization bill are gearing up for an expected Saturday vote in the Minnesota House.

The pressure is on House members as they look at approval of the measure that is a top priority for powerful unions and an abomination to many conservatives.

The debate over the measure took 17 hours to pass the Senate earlier this week, as Republicans inveighed against it and Democrats tried to defend it.

Already House Republicans have signaled their intention to make the debate last until the idea gets a full airing. They've filed nearly 100 potential amendments to the measure.  

Despite what is expected to be a tough slog, House Speaker Paul Thissen, DFL-Minneapolis, said late Friday night that he was "pretty confident" that the measure would eventually be signed into law this year.

Majority Leader Tom Bakk, DFL-Cook, concurred.

"I sure hope we didn't vote on it for nothing," he said.

If it became law, about 21,000 child care and home health care workers could unionize with AFSCME, the American Federation of State, County and Municipal Employees, or SEIU, the Service Employees International Union.

In recent days, Republican state representatives, and their allies, have encouraged opponents to come to the Capitol on Saturday to make their voices heard. 

"If this impacts you, I encourage you to come to the Capitol on Saturday when the House debates this unprecedented attempt to unionize small business owners in our state," Rep. Tony Albright, R-Prior Lake, said in an email to constituents. Other GOP members sent similar emails.

Backers are also getting their voices out. They've conduced a session-long lobbying effort and on Friday, the Alliance for a Better Minnesota, which spent millions to elect a Democratic Legislature last year, sent out an email to gin up mroe support.

"The ultra-conservative Koch brothers and Freedom Foundation are ginning up emails and calls from out-of-state to scare you into believing their false talking points. The calls and emails against the bill are coming from places like Kansas and Connecticut, not Minnesota," the Alliance said in an email.  The Alliance got large contributions from union groups and from Alida Messinger, a Rockefeller heir and Gov. Mark Dayton's ex-wife.

Ardent opponent of the unionization measure Rep. Mary Franson, R-Alexandria, said the accusation that resistance comes from out of state rings false.

"I am extremely disappointed with Alliance for A Better Minnesota lying to their members. Childcare providers, all over the state have been fighting this issue for over seven years. Their effort is grassroots in the truest sense and they are they are looking forward 'no' votes tomorrow," Franson said.

Chris Van Guilder, spokesman for the Minnesota chapter Americans for Prosperity, the group has sent out action alerts about the unionization bill to thousands of Minnesotans and have encouraged Minnesotans to oppose the measure. Nationally, Americans for Prosperity is supported by the Koch brothers.