BRUSSELS — Prime Minister Theresa May of Britain, who came to Brussels on Wednesday evening hoping to improve her chances of winning parliamentary approval for her plan for withdrawal from the European Union, is discovering once again that other nations of the bloc have domestic politics, too.
Her meeting with the president of the European Commission, Jean-Claude Juncker, was intended to push the British view on the last bit of unfinished business: a nonbinding political declaration, setting out the principles for Britain’s relationship with the European Union after the departure, a process known as Brexit.
There was no concluding news conference, but in a statement to the BBC issued after the meeting, Mrs. May said that she would return to Brussels for more talks on Saturday to try to conclude the deal before a special European Union summit meeting scheduled for Sunday. She provided no details on the sticking points.
The delays, coupled with disagreements between France and Germany about the text, may mean that the summit meeting itself is postponed.
But for Mrs. May, there is a form of success. She wants to be seen at home to be battling Brussels to get the best future arrangement for Britain — while trying to beat back the concerns of other member states, in particular France, Spain and some of the Scandinavian countries.
Mrs. May wants to add detailed language to the political declaration about a future of “frictionless trade” with the bloc and a currently nonexistent technological fix to avoid a hard border between Northern Ireland, which is part of the United Kingdom, and Ireland, which will remain in the European Union.
But other countries are piling in with their own demands, many of them aimed at their own domestic constituencies, diplomats said. The political declaration, which is still being negotiated, has stretched from the original seven pages to more than 20, according to diplomats.
France has been especially strong in demanding better guarantees for a “level playing field” for economic competition with Britain once it leaves the bloc but remains in a form of customs union for goods. The French have also pressed for assurances on fishing quotas, a major concern as well for Denmark, the Netherlands, Spain and Sweden.
The French have been so outspoken, one European official said, that it made him wonder whether Paris actually wants Britain to leave the bloc with no deal at all, though he believes that in the end France will go along with the rest.
The discussions between France and Germany have become so intense — with Germany wanting the deal done by Friday and France wanting to prolong the debate into Sunday — that there are some who worry that the Sunday meeting may not happen at all.
Spain, with its prime minister, Pedro Sánchez, ruling in a minority government, has responded to domestic criticism by insisting that it will oppose a Brexit deal unless there are guarantees that the future of Gibraltar, a British colony claimed by Spain, is left out of the agreement. His concern is that the colony’s future remains a bilateral issue.
Spain is likely to get some sort of guarantee or side-letter, known as a “declaration,” clarifying the point, and Spanish officials said on Wednesday that there had been some progress in easing their concerns.
Fish are also a sensitive issue. Future fishing quotas are so complicated that they were left out of the withdrawal agreement, postponed to the ensuing, post-Brexit negotiations on the details of a future relationship. But the issue is important to all countries concerned, with even the British fishing industry divided between those who live on exports to the European Union and those who sell domestically.
Both Britons and Europeans are upset that if a separate deal on fish is not done by July 2020, during the transition period the European fishing industry will lose access to British waters while Britain’s will lose access to European markets.
There are other concerns, noted Charles Grant, the director of the Center for European Reform, a research institution. Some countries known for their pragmatism, like the Dutch, the Swedes and the Baltic countries, are working on legislation to cover important trading issues with Britain in the case of a no-deal Brexit. But the European Commission wants them to refrain from doing so now, to keep pressure on Britain to complete and ratify the withdrawal agreement rather than “work to help the British mitigate with mini-deals in advance of a possible no-deal,” Mr. Grant said.
The European Central Bank is also discouraging countries from doing deals in advance on financial services.
The political declaration has to be approved alongside the binding withdrawal agreement, a nearly 600-page text of lawyerly clauses, which Mrs. May insists cannot now be altered. Both documents are required under the European Union treaty’s Article 50, which governs a country’s exit from the bloc.
The other European member states plan to approve both documents in a special summit meeting in Brussels on Sunday, and European officials hope that the texts will be finished by Friday to ensure a quick approval. But as ever in the European Union, deadlines can tend to slip.
Once agreed by the bloc, it is then up to Mrs. May to get the documents approved by the British Parliament, which is looking to be an extremely difficult task. Then they will receive final approval, with little fuss expected, from the European Parliament, so that Britain can exit in an orderly fashion on March 29 of next year.
European Union diplomats and officials emphasize that they do not want to do anything to make the embattled Mrs. May’s task harder. So they are trying not to fuel further bickering in her divided Conservative Party or within Parliament, where the withdrawal deal is already sharply criticized and her majority is threatened.
Mr. Grant predicted European approval of the deal on Sunday, despite the criticisms. “I think in the end it will be more theater than substance,” he said. But that will also be true for Mrs. May, who needs to be seen as standing up for British sovereignty in her dealings with Brussels.
The irony is that Britain has spent months trying to go around the bloc’s Brexit negotiator, Michel Barnier, and appeal to friendly countries like the Netherlands and Germany for support in the negotiations, a ploy that failed and annoyed other member states. But now that the bloc’s other member nations are more directly involved, they are raising objections to what they see as a good deal for Britain, all things considered, not the reverse.
“There is mounting frustration with Britain and a new readiness to express it in France and Spain,” said Simon Tilford, a British economist and expert on Europe. “But this is the withdrawal agreement only, so it’s a bit hard to understand why governments are frustrated. The withdrawal deal just opens the way to transition and negotiations on a future arrangement, with guarantees for Ireland, that’s all.”
As for the British, Mr. Tilford said: “There is little awareness of how frustrated, bemused and bored with the whole process much of the rest of Europe is. The inability of the Brexiters to step beyond their own self-anointed identity and see themselves through others’ eyes is staggering.”
Before flying to Brussels, Mrs. May told British legislators that rejecting her deal would mean “more uncertainty, more division, or it could risk no Brexit at all.”
That last warning was also emphasized by Amber Rudd, who has rejoined the cabinet. “I think people will take a careful look over the abyss,” Ms. Rudd said of Parliament, “and consider whether they think it is in the best interests of the whole country.” If they are not careful, she said, “the Brexiteers may lose their Brexit.”
Gibraltar has long been a thorn in the relationship between London and Madrid — and the border dividing the Rock and the Spanish mainland was closed entirely during part of Franco’s dictatorship. More recently, the border crossing has remained an issue, with Britain occasionally denouncing in Brussels the toughening of border checks that Madrid has justified as part of its attempt to combat smuggling, particularly of tobacco. Britain and Spain have also engaged in similar feuding over access to Gibraltar’s territorial waters.
Spain maintains that Gibraltar is a colonial relic that Britain should return, just as it did with Minorca, the island that it also formally took over as part of the 1713 Treaty of Utrecht. But Britain notes that the inhabitants of Gibraltar have voted overwhelmingly in favor of remaining British, including in a 2002 sovereignty referendum.