The next 10 days could make or break a plan to reshape the European Unionunder new management in an attempt to revive the economy and regain trust among its half-billion people.

From Monday, members of a European Parliament elected on a wave of anti-Brussels protest will subject nominees for posts on executive European Commission to hearings that could wreck the line-up and a complex new structure proposed by its incoming president, Jean-Claude Juncker.

The former Luxembourg prime minister has presented his team as "political, not technocratic", featuring several former premiers and fewer career bureaucrats.

But lawmakers are uneasy about several of his appointments and the nominees from Britain, France,Spain and Hungary face a torrid interrogation.

In making controversial choices for key roles, Juncker hopes to overcome member states' resistance to EU policies by handing their nominees power in areas where their government is at odds with Brussels.

By giving Britain's Jonathan Hill control of banking and Frenchman Pierre Moscovici charge of budget discipline, he aims to turn poachers into gamekeepers, winning London over to common EU financial rules and Paris to reforming state spending. Hill's hearing is on Wednesday and Moscovici's on Thursday.

His proposals have support from national leaders, including center-right ally German Chancellor Angela Merkel. One senior envoy in Brussels called Hill's nomination a "masterstroke".

But many in parliament have yet to be convinced, either by the nominees or by a new, two-tier hierarchy in the Commission.

The structure is meant to filter and restrain the flood of EU laws that angers many voters and focus on a few priorities, notably reviving an economy blighted by unemployment and responding to growing support for anti-EU nationalists by delivering popular, visible results. Critics say it could lead to turf wars and blur Commissioners' responsibilities.

Lawmakers eager to exercise one of their key powers over an executive made up of a nominee from each of the 28 member states have forced changes before. Five years ago, they prevented the current team led by Jose Manuel Barroso from taking office until he dropped three members and moved a fourth to a different post.

"BIG GAMBLE"

With the wisdom of decades of Brussels deal making, Juncker hopes parliament's support for his own appointment in a new process on which the main left and right parties collaborated can help spare his line-up the mauling given to Barroso.

Officials speak of a "non-aggression pact" with the center-left. But even those close to him call it "a big gamble".

Gianni Pittella, leader of the center-left group which came second in May's election to Juncker's center-right bloc, said on Friday after a series of meetings with the incoming president: "We will make sure all the commissioners face a very demanding level of scrutiny ... The battle is far from over."

The whole Commission stands or falls together, in a vote scheduled in parliament for Oct. 22. So if committees withhold confirmation for any nominee, the process by which Juncker is due to replace Barroso on Nov. 1 could be held up.

Party discipline is weak in the EU parliament, where a complex matrix of national loyalties, rivalries among various EU institutions and other factors make voting hard to predict.

Technically, the outgoing Commission would go on working. But delay could weaken the EU as it grapples with Russia over Ukraine and deals with stabilizing euro zone finances, negotiating on Iran's nuclear activity and exploring a transatlantic free trade pact with the United States.

Moscovici and Hill are sure of a grilling: German members do not trust a Socialist former French finance minister to penalize his own country for breaching euro zone deficit limits; the left doubts Conservative lobbyist Hill will curb excess in the City of London even though his portfolio will not regulate bankers' bonuses. One legislator called him a "fox in the henhouse".

Several other picks could trip Juncker up. Environmentalists are furious at the choice of Spain's Miguel Arias Canete for a newly combined energy and climate change portfolio, despite family interests in oil. His hearing is on Wednesday.

Tibor Navracsics from Hungary, whose brief covers education, culture and citizenship, faces a rough time convincing lawmakers concerned about his party's record on democracy. Ireland's Phil Hogan is embroiled in a political row at home. Alenka Bratusek lacks support from the Slovenian government, since she nominated herself while caretaker prime minister after losing an election.

STRUCTURE CONCERNS

Aside from personalities, the structure by which Juncker wants to introduce a layer of vice-presidents to coordinate overlapping clusters of commissioners troubles many lawmakers.

"It's a very strange organization," said French centrist Jean Arthuis, chairman of the budget committee.

While creating "clusters" of departments to set priorities was worthwhile, he said, the fact that vice-presidents would have minimal staff of their own was a concern.

Pittella of the center-left group said: "Negotiations are still ongoing on the new institutional structure Juncker has proposed and the role of vice-presidents."

His group opposes allowing the vice-presidents to block commissioners' proposing action by the Commission.

Juncker sees the structure as streamlining the organization, promoting collective action and preventing a proliferation of laws as commissioners, whose number has soared as the EU took in new members, seek to justify their existence.

Many lawmakers say they are puzzled about how decisions will be taken in a system where Moscovici, for example, runs economic policy but must report, for different parts of his portfolio, to two vice-presidents - from Finland and Latvia, both hawkish allies of Germany in the euro zone.

Juncker's decision to give Hill the financial regulation beat, including plans to develop an EU banking union of which Britain wants no part, was a conciliatory gesture to Prime Minister David Cameron, who had fought his appointment.

But it could backfire if lawmakers reject Hill, sparking another crisis with London ahead of a renegotiation of Britain's membership before an in/out referendum that Cameron has promised to hold in 2017 if he is re-elected next year.

If nominees are rejected, Juncker can reshuffle them into a different post or ask their government to nominate someone else.

The first to face their three hours of committee questions will be Malta's Karmenu Vella, charged with environment and fisheries, and Swedish trade commissioner nominee Cecilia Malmstrom. Their hearings begin at 2:30 p.m. (1230 GMT/8.30 a.m. EDT).

Sessions continue through the week, from 9 a.m. to 9 p.m. Most committees aim to make their decisions the same day.

Next week sees vice-presidents quizzed, including foreign policy chief Federica Mogherini of Italy. Last, on Oct. 7, will be Frans Timmermans, the former Dutch foreign minister who is Juncker's proposed right-hand man, overseeing the team.