Leaders to decide on EU future by end of year

"As we mark the 60th anniversary of the Treaties of Rome, it is time for a united Europe of 27 to shape a vision for its future," he said in his statement.

The plan is to get any one or a combination of the five ideas up and running by 2025 once decided by EU leaders at a summit scheduled for December.

Juncker's white paper, which outlines the plans, is also seen as a reaction towards growing populism in Europe and a follow-up to a summit on similar questions posed last year in Bratislava.

Juncker had already "tested" the white paper ideas following talks with Germany's chancellor Angela Merkel, Spanish prime minister Mariano Rajoy, and others since last year's Bratislava event.

Five scenarios

The scenarios are entitled "carrying on", "nothing but the single market", "those who want more do more", "doing less more efficiently", and "doing much more together".

The "carrying on" plan means the EU 27 would continue to operate as it does with priorities updated and legislation rolled out when needed.

The drawbacks, according to Juncker's so-called white paper, is that decision-making remains complex and delivery of policies does not match expectations.

The "nothing but the single market" means issues like migration, security, and defence would be no longer discussed or resolved at the EU level.

Social, environmental, development and human rights issues would also be left aside. With focus on the market, things like the free movement of people would be likely to suffer as EU states imposed more internal border checks.

The "those who want more do more" would revolve around a core set of EU states who want more integration in areas like taxation, while other EU states would be free to decide if they want to join them later on.

Such "enhanced cooperation" already exists to some extent under current EU rules in terms of setting up a European public prosecutor's office or creating a financial transaction tax.

The "doing less more efficiently" would move away from social and employment policies while focusing on trade, security, migration, defence, and borders.

That includes setting up a European Defence Union and having the EU's border agency Frontex manage external borders.

The final scenario "doing much more together" wold be likely to face a backlash from populist groups and governments who want to claw back sovereignty from the EU institutions.

It its also termed the "Verhofstadt option" in reference to Belgian federalist MEP Guy Verhofstadt, the leader of the Liberals group in the European Parliament and its chief man on Brexit, the scenario priorities security and defence.

It also entails increasing the EU budget backed by own resources and creating a fully-fledged economic, financial and fiscal Union.

Juncker is set to outline his preference at a state of the union speech sometime in September. But he also told MEPs that he rejected "the idea that the EU should be reduced to a free trade area."