In the editorial for edition 21.2 of Juncture, we assess the state of political leadership in Britain, in the face of widespread public disaffection and disengagement, and the rise of political populism here and abroad.

For all its occasional bitterness and rancour, both sides in the independence referendum in Scotland acknowledge that it galvanised a passionate democratic conversation about the future of the country. It was a process through which the popular sovereignty of the Scottish people was not only legitimated but given deep and wide expression. At stake was not just the question of who governs Scotland but how it is governed: whether remote elites or the people themselves should chart the course of the nation. In England, meanwhile, the rise of Ukip attests to a similarly deep frustration with the political status quo, albeit a frustration expressed in different tones and for different purposes than the Scottish debate. What is clear from both is that traditional political institutions and forms of political leadership are under real strain. In some crucial respects, the historic institutions, organisational forms and assumptions of mass 20th-century party politics have broken down.

This party conference special of Juncture focuses on the crucial question of political leadership, and whether it is possible to rehabilitate it as an effective force in the face of widespread disaffection with traditional political life. As Max Weber argued, politics is about passion, perspective, and the hard slog of reform. Without passion, it fails to grip. Without perspective, it too often falls prey to counterproductive populism. Without a commitment to undertake the 'slow, strong drilling through hard boards' necessary to achieve change, it is ineffective and eventually leads to alienation. The challenge for leadership, then, is to revive passion, perspective and the capacity of democratic action to achieve change despite the head winds of what Colin Crouch has called an approaching 'post-democratic' age.

Here, Michael Kenny and Nick Pearce argue that political leaders can effectively meet this challenge, but only if they respond to the widely held desire for popular self-government, becoming more pluralistic, democratic and experimental in the process – and all the while resisting the short-term fixes of populism, whatever its guises. Political parties, politicians and civic society, they argue, require greater autonomy and decentralisation, with more routes into political life, if we want a stronger, more representative democracy. David Runciman's essay, meanwhile, explores whether it is the relative lack of stature in today's political class that breeds disaffection. Has the age of political giants passed, as it is sometimes claimed? Or do we in fact need to measure today's politicians against new yardsticks to test for aptitudes that better reflect political realities in 21st-century Britain?

Against this background, how will history judge the leadership of our current prime minister? The historian Anthony Seldon presents his first cut on the Cameron premiership (his fully authorised account will appear next summer). The judgment of history, he contends, will be far less dependent on whether Cameron wins the outright majority in 2015 that so many Tories crave, and which he failed to achieve in 2010, than on Cameron's success at holding the Coalition – and the social fabric of the country – together in profoundly challenging times. Seldon argues that Cameron's skills as a leader were ideally suited to the fudges and compromises of coalition politics. Yet, however at home Cameron is in the land of 'the Quad', he nevertheless failed, Seldon argues, to respond to or take seriously the Ukip threat, with all the dire consequences this has had for Conservative party unity. His leadership attributes are, in other words, too one-dimensional to cope with the multifarious challenges thrown up by the rising tide of anti-politics sentiment that Kenny and Pearce describe.

As Isabel Hardman argues, the prime minister remains captain of an unruly Tory ship – the defection of Douglas Carswell as a Ukip MP merely one of the most recent examples – and there are many rocky channels he must yet navigate if he is to arrive safely back in Number 10 in May. His coalition partners in the Liberal Democrat party face a similarly tricky challenge, Miranda Green argues, in balancing insurgent radicalism with the hard-won mantle of credibility earned in government. Rounding off this assessment of the immediate futures of the UK's main political parties, John Curtice's regular column suggests that this coming general election is without precedent. A fixed-term parliament, an incumbent coalition government and an insurgent fourth party in the form of Ukip mean that Labour's path out of opposition is far less predictable than in the past. Yet if there continues to be a 'voterless recovery' for the Tories then even a narrow Labour lead, he argues, could prove sufficient to deliver victory, albeit without a majority.

What is clear is that whichever party or parties govern after May 2015, questions of popular sovereignty will continue to underpin much of our contemporary debate. In this edition, the intellectual historian Quentin Skinner explores the basis on which a government might seek to justify the use of discretionary and arbitrary powers over its citizens, arguing that taking republican liberty seriously requires a fundamental constitutional revision in the UK. In response, Hannah Dawson challenges us to move beyond a limited view of representation and towards a wider recognition of the benefits of having leaders who more closely resemble society, while Anthony Barnett argues that British political elites have long fostered an institutional culture that perpetuates and legitimises their arbitrary powers, a situation incompatible with thoroughgoing popular sovereignty and this digital age.

British politics cannot return to the status quo after the tumultuous events of recent months. The democratic conversation that animated the Scottish referendum must spread to England, Wales and Northern Ireland. Howsoever it is given institutional or political expression, popular and representative engagement in the renewal of our democracy is now imperative.

This article appears in edition 21.2 of Juncture, IPPR's quarterly journal of politics and ideas.