The EU has long had a problem of legitimacy, but the euro crisis has made it worse. According to Eurobarometer, 72 per cent of Spaniards do not trust the EU. The Pew Research Centre finds that 75 per cent of Italians think European economic integration has been bad for their country, as do 77 per cent of the French and 78 per cent of the Greeks.

For more than 60 years, the EU has been built and managed by technocrats, hidden from the public gaze – or so it has seemed. In fact national governments have taken most of the key decisions, but public scrutiny has been insufficient. This model cannot endure, because the EU has started to intrude – particularly in the euro countries – into politically sensitive areas of policy-making.

Political institutions can gain legitimacy from either ‘outputs’ or ‘inputs’. The outputs are the benefits that institutions are seen to deliver. The inputs are the elections through which those exercising power are held to account. The euro crisis has weakened both sorts of legitimacy.

The outputs are hardly impressive. Economies are shrinking in many member-states, credit is in short supply in southern Europe, unemployment in the eurozone is over 12 per cent, and youth unemployment in Greece, Italy, Portugal and Spain is between 40 and 65 per cent. Neither the EU nor the euro appears to be delivering much in the way of benefits – whether to Greeks who blame Germans for austerity, or to Germans who resent contributing to Greek bail-outs.

Input legitimacy has also suffered. Given the complexity of decision-making, with power shared among many institutions, lines of accountability in the EU have never been easy to follow. But the perception that power is unaccountable is growing, especially in the heavily-indebted eurozone countries.

Power over economic policy has flowed away from national parliaments and governments to financial markets and to unelected institutions. Having mismanaged their economies, Greece, Portugal, Ireland and Cyprus have had to negotiate programmes of deficit reduction and structural reform with the ‘troika’ of the European Commission, European Central Bank and International Monetary Fund. Other countries, such as Italy, Spain and Slovenia, have avoided full bail-out programmes but had to follow the Commission’s budgetary prescriptions in order to avoid reprimands and possible disciplinary proceedings. Decisions on bail-outs and the conditionality that applies to them have been taken by eurozone finance ministers and heads of government. It is not at all clear where and how such decisions can be held to account, as became evident during the messy rescue of Cyprus in March.

There is no silver bullet that can suddenly make the EU respected, admired or even popular among many Europeans. Its institutions are geographically distant, hard to understand and often deal with obscure technicalities. However, unless the EU becomes more legitimate and credible in the eyes of voters, parts of it could start to unravel. For example, at some point eurozone governments may seek to strengthen their currency by taking major steps towards a more integrated system of economic policy-making. But then a general election, a referendum or a parliamentary vote could block those steps and so threaten the euro’s future.

The best way to improve the EU’s standing would be to improve its ‘outputs’. If European leaders moved quickly to establish a banking union, to strengthen the EU’s financial system; if Germany did more to stimulate demand, thereby helping southern European economies to grow; if structural reform started to restore the competiveness of those economies; and if unemployment started to fall – then EU leaders would look competent, and support for eurosceptics and populists would wane. For the most part such outcomes require not new institutions, but better policies.

Nevertheless EU governance is in bad need of an overhaul. For many federalists, the answer to perceptions of a democratic deficit is simple: when decisions take place at EU level, the European Parliament should exercise democratic control (alongside the Council of Ministers). And if more decisions are being taken at EU level, the powers of the Parliament over them should grow.

However, these arguments face both practical and theoretical difficulties. The practical problem is that the Parliament has serious shortcomings as an institution. Since its first direct elections in 1979, four major treaties have boosted its powers. MEPs now have considerable sway over the EU’s laws, budget and international agreements. Yet in every European election, the turn-out has declined – from 63 per cent in 1979 to just 43 per cent in 2009.

MEPs do a good job in some areas. In recent years they have, for example, improved the directive on hedge funds and private equity, and helped to reform the Common Fisheries Policy. But few voters are aware of the Parliament’s good work and many of them are sceptical that MEPs represent their interests; a lot of MEPs have little connection to national political systems.

Much of the time, the Parliament’s priority appears to be more power for itself. Since the 2009 European elections, MEPs have increased their hold over the Commission, and not only because of the extra powers the Lisbon treaty gave them. One of their techniques is to block what the Commission wants in one area, in order to extract a concession in another. The Parliament always wants ‘more Europe’ – a bigger budget and a larger role for the EU – but there is little evidence that most voters think the same way.

There are also theoretical objections to the Parliament becoming the main body for democratic oversight of the eurozone. In the EU’s usual law-making procedures – known as the ‘community method’ – the Parliament plays an important role. Thus in the last few years it has amended and approved new laws on eurozone budgetary discipline. And it is probably the best-placed body to question the Commission on its monitoring of member-state economies.

However, the money that rescues heavily-indebted member-states has to be voted by national parliaments. The EU budget is not involved to a significant degree, so the European Parliament plays only a minimal role in bail-outs. Decisions on bail-outs and the conditionality that applies to them are taken at EU level by eurozone finance ministers and heads of government. But these decisions have to be implemented by national parliaments: the German Bundestag had to vote money for Cyprus’s bail-out, while the Cypriot parliament had to approve the winding up of Cypriot banks.

These are reasons to increase the involvement of national parliamentarians in eurozone governance – and in the EU more broadly. Critics of their involvement argue that most of them focus on national issues and have little understanding of the wider European interest. Those are valid points. Any attempt to enhance the role of members of parliament (MPs) therefore needs to encourage them to ‘think European’. The European Council has helped heads of government to do so. The prime ministers who attend wear two hats – as national political leaders and members of the EU’s supreme authority. As Luuk van Middelaar, an adviser to Herman Van Rompuy, demonstrates in his excellent new book ‘The passage to Europe’, when national leaders attend the European Council, they start to consider the European interest – sometimes to their own surprise.

So how can MPs play a bigger role in scrutinising the EU? There are increasing numbers of ‘inter-parliamentary’ bodies that bring together MPs and MEPs. These range from the general Conference of European Scrutiny Committees (COSAC) to more specialised groups for foreign policy and Europol. And the recent fiscal stability treaty set up a ‘conference’ that will gather MPs and MEPs to scrutinise the operation of the treaty and discuss wider economic issues. However, these bodies – though useful – are merely consultative and are often treated disdainfully by MEPs. They do not give MPs a sufficient stake in the EU.

Accountability should start at home. Some parliaments, such as that of Denmark, have good systems for holding ministers to account, before and after they attend the Council of Ministers. Others, including that of Britain, scrutinise draft EU laws but do not follow Council meetings closely. National parliaments could improve their systems by emulating best practice across the Union.

The links between national parliaments should be strengthened. The Lisbon treaty created the ‘yellow-card’ procedure, whereby if a third or more of national parliaments believe that a Commission proposal breaches subsidiarity – the principle that decisions should be taken at the lowest level compatible with efficiency – they may ask that it be withdrawn. The Commission must then do so or justify why it intends to proceed. So far this procedure has been used just once, when the Commission withdrew a measure that would have enhanced trade union rights. A small treaty change could turn the yellow-card procedure into a red-card procedure, so that, say, half the national parliaments could force the Commission to withdraw a proposal. A similar system could enable national parliaments to club together to make the Commission propose the withdrawal of a redundant or unnecessary EU law.

A more fundamental reform would be to implement the long-discussed idea of establishing a forum for national parliamentarians in Brussels. The forum’s workload should be modest, so that the best and brightest MPs would want to participate. It should not duplicate the legislative work of the European Parliament. Rather, the forum should ask questions about, and write reports on, those aspects of EU and eurozone governance that involve unanimous decision-making and in which the Parliament plays no significant role.

This forum could become a check on the European Council. It could challenge EU actions and decisions that concern foreign and defence policy, or co-operation on policing and counter-terrorism. On eurozone matters the new body could – meeting in reduced format, without MPs from non-euro countries – question the euro group president or give opinions on bail-out packages. The forum could start work as an informal body and, if it proved useful, be given formal powers – such as the election of the euro group president – through a new treaty.

Hopefully, the forum would encourage MPs to think European. Sceptics and cynics will rightly argue that a new institution cannot on its own make the EU accountable. But in the long run, MPs will have to become more involved in the workings of the EU. Because MPs are usually closer to their constituents than MEPs, and because they are elected on a higher turnout, they stand a better chance of improving the EU’s legitimacy.

Charles Grant is director of the Centre for European Reform.