If no deal is reached, more than 30,000 members of United Teachers Los Angeles wouldn't go to work, affecting roughly 480,000 public school students.
The union has been holding out, primarily, for the district to reduce class sizes and hire more nurses, librarians and counselors, all of whom the union also represents. District leaders have resisted, saying they don't have the money to pay for the level of changes the union wants.
In August, 98 percent of union members voted to authorize a strike. But California law requires certain steps be taken before teachers can walk out, among them state mediation and fact-finding. As of Tuesday, those measures have failed to bring about an agreement.
United Teachers Los Angeles had planned a possible strike as soon as Thursday, but that may be delayed until Monday due to a disagreement over when and whether the union filed formal notice of its intent to strike.
What a strike would mean for parents
LA Unified School District officials have told parents that if teachers go on strike, the district's schools would remain open for the same hours, offering the same before- and after-school programs.
About 81 percent of LA public school students rely on the district's free- or reduced-price meals, and schools would continue to serve those as well.
The district also says students who attend school during a strike would continue to receive instruction from "qualified L.A. Unified staff," including administrators — though it remains to be seen how the district could fulfill this promise.
United Teachers Los Angeles recently criticized the district's decision to hire about 400 substitutes, calling the move "illegal."
Still, district officials concede attendance is likely to plummet. Since the state funds schools based on how many students actually show up each day, even a short strike would be costly to the district.
Many LA parents plan to keep their children home in the event of a strike, some in a show of solidarity with the union, some because of uncertainty about how their kids will be supervised in the teachers' absence. For many of those parents, child care could pose a challenge.
The issues at stake
Negotiations between the district and United Teachers Los Angeles started in early 2017. Since then, contract talks have dragged on with little progress. Union members have been working without a contract for more than a year. There have been several hurdles to establishing a new agreement:
District finances. The two sides don't agree on how much money the district has available to spend on teacher demands. District leaders have said the union's proposals could "bankrupt" the school system, and they say they're not being hyperbolic. But union leaders don't buy these grim forecasts, saying none of the recent projections of the school district's financial collapse have come true.
The district has nearly $2 billion in the bank, and the union wants those funds spent on its contract demands. The district says it needs to put that money toward regular operations in order to avoid insolvency and to fend off regulators, who recently warned that the district risks being taken over by state or county officials.
Class sizes. The union wants to remove contract language that allows district officials to increase class sizes in order to save money. (After all, more students per classroom means less need to hire teachers.) In recent years, the district has unilaterally raised some class sizes to as high as 46 students, surpassing the 39-student limit spelled out in the last teacher contract.
School district leaders have offered to get rid of this language, but union leaders doubt the sincerity of the offer, in part, because the district has proposed a replacement provision that they feel would be worse.
District officials have also offered to spend $105 million on class size reduction.
Union officials want more ambitious (and costly) reductions to class sizes and special education teachers' caseloads. The district says it can't afford to do more.
Staffing levels. Some LA public schools operate without full-time librarians or nurses. The union wants to change that; it's calling for a full-time nurse for every school and a full-time librarian for every middle and high school. The union has also called for hiring a raft of new counselors, deans and social workers, all of whom the union also represents.
The district has said it would fold in more nursing, library and counseling resources into its $105 million class size offer. They believe that would allow them to double nursing services and provide library services at every middle school. In July, the district estimated that accepting all of the union's staffing demands could cost hundreds of millions of dollars.
Teacher pay. The two sides aren't far apart on salary, but the union is still hoping for a 6.5 percent raise — including back pay to July 2016. The district is offering a package of raises totaling 6 percent, but with back pay going back only as far as July 2017, when the teachers' last contract expired.