Leading article: Nick Clegg's opportunity to make his case

These have been a difficult few months for the Liberal Democrats. The opinion polls point to a sharp drop in support for Nick Clegg's party. This is what usually happens to the third party in the wake of an election. But a fall in the Liberal Democrats' media profile is normally the cause. This time the opposite has been the case.

The party's prominent coverage is the problem. Many who voted for the Liberal Democrats in May are angry with the party for forming a coalition with the Conservatives. Every public appearance of a Liberal Democrat minister seems to compound the offence.

There is growing discontent from the Liberal Democrats' activist roots, too. At the weekend, the party's deputy leader, Simon Hughes, felt it necessary to rule out the prospect of a non-aggression pact between the two governing parties at the next election to assuage fears of the Liberal Democrats being swallowed up by the Conservatives.

And the public spending cuts, which are likely to result in further public anger, have not even begun. The Liberal Democrats have been described as David Cameron's "human shield" against his own party's right wing, enabling the Prime Minister to enact more progressive policies than he would otherwise be able to get through. But that human shield tag might have a broader application. The danger is that the Liberal Democrats will end up taking the brunt of the public brickbats for the coming cuts, too. The Liberal Democrats have also had a harder time than their Conservative partners in explaining the compromises made on the road to coalition. The explanations of Mr Clegg, Chris Huhne and Vince Cable over why they changed their minds on the need to begin cutting the deficit immediately have been less than convincing.

Yet Mr Clegg has an opportunity over the next fortnight to get on the front foot. The Deputy Prime Minister will be the public face of the Coalition while Mr Cameron is on holiday. Mr Clegg's objective, in his series of "town hall" meetings, will be to articulate the achievements of his party in its first taste of government for seven decades and to demonstrate what Liberal Democrat supporters have got out of the deal.

The good news for Mr Clegg is that those achievements are real. There has been a reversal of Labour's instinctive disregard for civil liberties. The Coalition has agreed that schools reform will be accompanied by additional funds for institutions that take in less well-off children. There has also been a rise in the tax threshold for low earners; a commitment to reduce the rates of incarceration; consideration of a graduate tax to replace university tuition fees; and, most important of all, a date for a referendum on the Alternative Vote. There was significant Liberal Democrat influence on most of these progressive policies. Some would never have happened without their presence around the Cabinet table, particularly the vote on electoral reform.

Recent history is painful for Mr Clegg and he will doubtless be keen to avoid going over old ground as he tours the country. But it is worth recalling the circumstances in which this coalition came about. The parliamentary votes for a viable Labour-Liberal Democrat coalition were never there. Despite the public opprobrium the party is suffering now, the greater risk for the Liberal Democrats over the medium term would have been propping up a weak Labour Government or shying away from the compromises necessary to form a coalition. Such a response would have left the party looking like either an unofficial adjunct of Labour or a glorified pressure group unable to handle power.

Mr Clegg and his party have suffered the pain of that fateful decision. Now they need to maximise the gain. The merit of the Office of the Deputy Prime Minister is that it constitutes a sort of bully pulpit. Mr Clegg must make sure his positive sermon is widely heard.