NAMUR, Belgium — Wallonia, which is not even a country, is proving how difficult it is for the European Union to set policy for its 28 nations. A landmark trade deal with Canada is at the mercy this week of a decision in the regional parliament of this sub-region of Belgium.

The agreement has already been backed by an overwhelming majority of the member nations in the bloc of half a billion people and is earmarked to be officially signed at an EU-Canada summit in Brussels in two weeks.

Not so fast, says Wallonia, the Francophone region of this multilingual nation of 11 million. Under Belgium’s byzantine constitutional arrangements to appease their French and Dutch-speaking populations, all national and regional bodies need to back such trade deals for them to go ahead. With the rest of the EU, and Canada, looking on, it heaps enormous pressure on the Walloon legislature in southern Namur, which should decide on Friday.

That pressure only grew on Thursday, when Germany’s constitutional court rejected calls from opponents of a trade deal they claim is undemocratic for a legal injunction that had the potential to spell an end to the pact.

EU ministers are to decide whether to give their full backing at a meeting in Luxembourg next Tuesday, leaving all eyes centered on the 3.5 million people of Wallonia, a region of rolling pastures and woods as well as a string of poor rust-belt towns looking at an uncertain future.

“There is a lot of fear involved because we don’t know where we are going,” said local cow farmer Marc Decoster, who is scared a deal with Canada will leave the farm sector too exposed to cheaper imports from industrial Canadian farms. Environmental activists and trade unions have all warned such international deals could worsen local standards for food, work and industry.

“We arrived at the conclusion in April this year that we could not sign this treaty and we named a certain number of concerns that were not met,” Wallonia parliament president Andre Antoine told The Associated Press on the eve of the decision.

The EU says the Comprehensive Economic and Trade Agreement deal with Canada will improve trade, create jobs, will remove just about all tariffs and custom duties while at the same time guaranteeing European standards on anything from food and health quality to labor rights.

“This treaty has, in a number of issues of market access and investment, reached a stage that is infinitively better that in any other trade treaty so far, without in any way, directly or indirectly, threatening the level of safety health and environment protection that we already have,” said Jacques Pelkmans, senior research fellow at the Center for European Policy Studies.

Like so many others, he is frustrated that rejection by part of one nation, however small, could destroy the deal, and said it would undermine the credibility of the whole EU. Because the EU consists of independent nations, often wary of giving up powers to Brussels, there are many checks and balances that give national capitals veto rights on a slew of issues.

If Wallonia can scuttle the deal, said Pelkmans, it would finish off EU trade policy “because now it is the Walloon parliament, tomorrow it is the Brussels parliament, tomorrow it is Malta… There is no end to this.”

For many, the CETA is only a prelude to the even bigger free trade deal, called TTIP, that is being negotiated with the United States, and which has given rise already to massive protests in several member states, including Belgium — and Wallonia.

“We know well that after CETA there will be TTIP and we have a model of society that it is not the same as the Americans or the Canadians, so we propose another treaty in which the features that do not please us are corrected,” Antoine said.

Casert reported from Brussels.