Sunday's European Council summit seemed to be over before it started.

German Chancellor Angela Merkel's conservative European People's Party (EPP) rebelled forcefully against a plan developed by EU leaders on the sidelines of a G20 summit in Japan's Osaka that would have installed a Social Democrat, Frans Timmermans, as the next Commission president.

Conservatives, gathered for a pre-summit party meeting, reacted with unbridled fury at the proposal. It envisioned the long-dominant EPP give up the presidencies of the Commission and the Council, while retaining only the presidency of the European Parliament and the position of high representative of foreign affairs.

Among the national leaders to speak out against the proposal were Bulgarian Prime Minister Boyko Borisov, Croatian Prime Minister Andrej Plenković, Hungarian Prime Minister Viktor Orbán, and Irish Prime Minister Leo Varadkar. That opposition, along with Poland, Romania and other countries that had already voiced resistance to Timmermans, was enough to make the Osaka plan a political nonstarter.

Council President Donald Tusk put forward the proposal to leaders of the Parliament earlier on Sunday just hours after landing back in Brussels from Japan. He and his aides had warned that it was far from clear that the package — developed by Merkel, French President Emmanuel Macron, Dutch Prime Minister Mark Rutte and Spanish Prime Minister Pedro Sánchez — would succeed.

"There's no support from EPP leaders and EPP presidency for the proposed package" — Croatian Prime Minister Andrej Plenković

“As EPP, we haven’t agreed to the package that was negotiated in Osaka. I think it’s fair to say there’s a lot opposition to the proposal that was made in Osaka from the EPP’s point of view," Varadkar said, arriving at the Council's Europa building. "The vast majority of the EPP prime ministers don’t believe that we should give up the presidency of the Commission quite so easily, without a fight.”

Some EPP officials and diplomats said the deal appeared to be engineered to benefit Germany and especially Merkel in her relations with her governing coalition partner, the Social Democratic Party. In addition to elevating Timmermans — who is currently the Commission first vice president — to the top job, the plan envisioned the EPP nominee, German MEP Manfred Weber, becoming president of the Parliament for a double term of five years.

In a sign of the acute trouble facing the proposal, the Council summit dinner, scheduled to begin at 6 p.m., had still not started more than two hours later.

Plenković, who is believed to harbor his own aspirations for a top EU job, flatly dismissed the Osaka plan.

Officials and diplomats said that Tusk had lowered his expectations for the Sunday summit and believed a deal would be impossible to reach.

"There's no support from EPP leaders and EPP presidency for the proposed package," Plenković said, adding that the party stands behind Weber. "Socialists and liberals are trying to disqualify Weber without any credible arguments," he added. "The negotiations will be long and exhaustive."

"This deal is good for Germany, not for the EPP. Some leaders are rebelling against it," an EU diplomat said. The EPP leaders met shortly after their arrival at the summit venue in the offices of the Latvian delegation to develop common talking points, the diplomat said.

Borisov, arriving at the summit, said that Weber remains the EPP nominee for Commission president, and he complained that no matter what might have been developed in Osaka, the four leaders behind the proposal do not speak for the 24 others on the Council.

Officials and diplomats said that Tusk had lowered his expectations for the Sunday summit and believed a deal would be impossible to reach.

A second diplomat said that Tusk, in a meeting with Slovak Prime Minister Peter Pellegrini, told him that a deal is unlikely to come together on Sunday night.

As word spread of the opposition to the Osaka plan, officials and diplomats said a flurry of names were back under discussion for the EU's top job, including the liberal competition commissioner, Margrethe Vestager, who is Danish, the conservative Brexit negotiator Michel Barnier, who is French, and the conservative chief executive of the World Bank, Kristalina Georgieva, a Bulgarian.

Further complications ahead

The deadlock raised the prospect that the Council would fail to settle on a leadership package before the new Parliament sits for its first plenary this week in Strasbourg, where it must elect a president.

That election alone stands to further complicate the already excruciating leadership deliberations. The EU treaties require leaders to seek balance in filling the top jobs, taking into account numerous factors, including party affiliation, geography and population size. The leaders are also seeking to increase the number of women in top EU jobs.

As a result, allowing Parliament to act first potentially constrains the options of the leaders in filling other posts, which include the Commission and Council presidencies, the high representative and the president of the European Central Bank. The bank post is somewhat distinct because of the special skills it requires and the bank’s independence, but the nationality of candidates is still a factor.

Several EPP officials said Merkel left the EPP’s pre-summit meeting before it ended after trying in vain to defend the Osaka deal. She arrived at the summit more than an hour ahead of her fellow conservative leaders.

“We will say no,” said Frank Engel, a member of the EPP from Luxembourg who participated in the EPP pre-summit discussions.

“This easy solution is not up to the EPP’s importance,” Engel said. “We are not going to accommodate all those who want to be served first.”

The alternative is, Engel said, that “we start negotiating.” He added that rank-and-file EPP members are “fed up” with the two other political families, the liberals and Socialists — “one more minor than the other” — dictating their wishes.

Parliament President Antonio Tajani, also with the EPP, said that respecting the election result is crucial. "We need to reduce the distance between the citizens and the European institutions — to have the Spitzenkandidat [Manfred Weber] as president of the Commission is a good message to the European citizens," he said.

The conservatives won the most seats in Parliament during the May European election, but lost seats overall compared with 2014.

Merkel remains the EPP’s most influential national leader and she was at the core of the discussions that led to the Osaka proposal, including a dinner in Berlin where she gathered Weber, the EPP President Joseph Daul and other leaders.

But having already announced that she is serving her last term, and with her own governing coalition in Berlin widely viewed as shaky, it was clear that Merkel’s sway over the party has diminished, and some party members openly questioned her motivations in supporting the plan.

“Mrs. Merkel represents Germany, not the EPP,” Paolo Rangel, a Portuguese MEP and one of the vice presidents of the EPP who attended the pre-summit meeting said.

Rangel noted that the EPP had officially tapped two other prime ministers, Plenković and Latvian Prime Minister Krišjānis Kariņš, as its official negotiators in the leadership deliberations. “Mr. Plenković and Mr. Karins,” Rangel said. “They speak on behalf of the EPP.”

Lili Bayer, Florian Eder, Eline Schaart and Zosia Wanat contributed reporting.