Monsanto’s flagship weed killer, Roundup, has had a tough year. And it could get worse.

With Roundup at the center of a federal case in the United States over claims that it causes cancer, European Union officials will meet in Brussels on Thursday as they weigh whether to allow the continued use of products that contain Roundup’s active ingredient, glyphosate, in its 28 nations.

Because Europe makes such decisions the way Americans vote for president — with a weighted vote among its member states — the outcome is tricky to predict.

A final decision, already long delayed, is not expected until later this year. France and Italy have indicated they will oppose the reauthorization, while Germany’s position remains unclear. A range of outcomes are possible, including phasing out Roundup and similar products entirely or limiting the length of their reapproval.

While Roundup still enjoys broad support among farmers and a number of European governments, sentiment against its maker is at a low point in Europe, with a petition campaign against glyphosate reportedly surpassing one million signatures. Last week, the European Parliament also made Monsanto the first company barred from lobbying the chamber after its executives refused to take part in a hearing over glyphosate. Monsanto viewed the hearing as a political sideshow.

“We are ready and willing to engage the European Parliament and policy makers in Europe,” said Scott Partridge, Monsanto’s vice president of global strategy, in an email. But, he added, “this particular forum was not set up for substantive discussion related to the regulation and use of glyphosate.”

Monsanto, which is in the process of being acquired by Bayer, also faces litigation in the United States from farmers, members of their families and others who claim that Roundup is connected to non-Hodgkin’s lymphoma. The litigation has led to embarrassing questions about whether the company had engaged in ghostwriting of news articles and academic papers.