FACTBOX: EU's reform treaty, main points

(Reuters) - European Union leaders signed the Treaty of Lisbon on Thursday to reform the bloc's institutions and give it stronger leadership, marking the end of a difficult process that has lasted nearly a decade.

The text incorporates key reforms in the constitution rejected by French and Dutch voters in 2005 while discarding the name, structure and symbols.

Here are some of the main points of the 250-page treaty, due to be ratified by 2009.

INSTITUTIONS - EU leaders will choose a president of the European Council for 2-1/2 years renewable to strengthen the current system of rotating presidencies.

A powerful new foreign policy chief, at the head of an EU foreign service, will give the bloc a greater say on the world stage. The High Representative will answer to EU governments but also be vice-president of the European Commission and manage the EU executive's large external aid budget.

The Eurogroup of finance ministers of countries that share the euro single currency is formalized for the first time and elects a chairman for a renewable 2-1/2-year term.

Member states will benefit from a NATO-style mutual defence clause in the case of one of them being attacked.

The European Court of Justice will be given more power by being allowed to rule for the first time on whether national legislation on justice and home affairs is compatible with EU laws -- except for Britain and Ireland, which secured opt-outs.

The European Commission, the EU's executive, will have fewer members from 2014. Each of the EU's 27 nations now appoints a commissioner but the size will be capped at two-thirds of the number of member states.

The number of seats in the European Parliament will be increased to 751 from 736 envisaged in the last treaty.

VOTING - EU decision-making will continue to be based on the present unwieldy weighted voting system agreed in the 2000 Nice Treaty until 2014.

After that, voting will be based on a more democratic "double majority" system requiring 55 percent of member states representing 65 percent of the EU population to pass a decision.

From 2014 to 2017 any country can ask to revert to the old rules in any vote. States just short of a blocking minority may invoke a mechanism to delay EU decisions for several months.

The treaty allows decision-making in more policy areas by majority voting, notably in justice and home affairs. Foreign policy, tax matters and EU budget and revenue decisions will continue to require unanimity.

Britain and Ireland won the right to opt out of closer police and justice cooperation, but not to stop other member states moving ahead without them.

National parliaments will be given a say in drafting EU laws. They will review draft proposals, and if one-third of them reject it, the European Commission will have to change it.