MADISON, Wis. — The Republican-led Legislature is considering making Wisconsin a right-to-work state, in which unions would be prohibited from reaching labor deals with businesses that require private-sector workers to pay union fees. Here are things to know about the developments in the fast-moving debate:

WHAT HAPPENED MONDAY:

The Senate and Assembly approved calling an extraordinary session to take up the right-to-work bill, which was also formally introduced in the Senate. The votes to call the session broke down along party lines, with Republicans on organizational committees in support and Democrats against. The votes were cast via paper ballots, so there were no actual meetings. Republicans have an 18-14 majority in the Senate and a 63-36 advantage in the Assembly.

UNION REACTION:

Public and private-sector union leaders urged their members and business owners to put pressure on lawmakers to vote against the bill. But Sally Feistel, a United Steelworkers union leader from Menasha, said she believes it's inevitable that the bill will pass. She and others speaking at a news conference decried right to work as an attack on working families, saying it will lead to lower wages, less safe working conditions and a decline in training. Unions speaking out against the measure Monday included the AFL-CIO, the Wisconsin Federation of Nurses and Health Professionals, the operating engineers, the Wisconsin state employees union, the American Federation of Teachers, the Wisconsin Education Association Council, the Building Trades Council of South Central Wisconsin, machinists, laborers, United Food and Commercial Workers and the United Auto Workers.

WHAT ABOUT PROTESTS?

Unions are organizing noontime rallies at the Capitol on both Tuesday and Wednesday, but it wasn't apparent yet whether they will reach the size of the protests that came four years ago when the Legislature took up the bill targeting collective bargaining for public employees. Phil Neuenfeldt, president of the Wisconsin state AFL-CIO, said he wanted to ensure that people had an opportunity to have their voices heard both at the hearing and at the rallies but "it's unclear how many people will show up," The largest of the 2011 protests over union rights attracted about 100,000 people. Cullen Werwie, a spokesman for Gov. Scott Walker's administration, said police will "work to keep the Capitol open and accessible as visitors come to share their opinions."

WHAT SUPPORTERS ARE SAYING:

Wisconsin Manufacturers and Commerce, which represents 3,800 large and small manufacturers and companies, local chambers of commerce and specialized trade associations, spoke out in support of the measure on conservative talk radio in Milwaukee and through a video press release. WMC lobbyist Scott Manley cast the issue as about worker freedom, saying making Wisconsin the 25th right-to-work state will help the economy and attract more jobs. Manley said the Legislature has an "historic opportunity" to pass the bill.

WHAT HAPPENS NEXT:

The Senate Labor Committee scheduled a public hearing on the issue beginning at 10 a.m. Tuesday. The hearing is scheduled to last until 7 p.m., with a vote to follow. The full Senate planned to debate it Wednesday, with a vote later that day or Thursday. The Assembly was to take it up next week. Walker has said he will sign the bill into law.