The Chinese, according to John F Kennedy, use two brush strokes to write the word "crisis". The first stands for danger; the other for opportunity. Still smarting from the House of Lords reform debacle, Nick Clegg faces both in equal measure.

The increasingly strained relationship with the Conservatives provides him with room for manoeuvre, perhaps more than he realises. For the first time, the Liberal Democrats can operate in the way they should always have done – as an independent party that has chosen to ally itself with another to run the country for a specific period. They need make no more claims than this. They need to keep their options open and to be seen to be doing so.

Clegg trades on the fact that he is the first peacetime Liberal in a century to preside over government. That is no mean feat and, by the nature of coalition, requires compromise. The public appears to appreciate, better than the Westminster village, that give and take is a sign of a mature political system.

His problem, however, has not been the fact of compromise, but its nature. Most of the cases that he can demonstrate are negative ones. The Lib Dems have played a vital role in making Tory legislation less extreme, less red meat. The health reforms could have been worse; Europe policy would have been more barking; welfare changes would have hurt the vulnerable even more.

The same would have applied had a post-2010 Lib-Lab coalition been formed. Labour is showing every sign of tacking to the right on criminal justice and civil liberties, continuing a miserable tradition established under the Blair and Brown administrations. What galvanises the troops, however, is positive change. The Protection of Freedoms Act, which received royal assent in May, was a small but important step forward in limiting the authorities' use of individual data. This is in danger of being more than offset by the hideous "snoopers' charter" and plans to introduce secret courts for intelligence-related criminal cases, such as the use of torture.

The pupils' premium and the raising of the income tax threshold are the most visible Lib Dem contributions so far. They need to be developed more in policy terms and trumpeted more as achievements. But these two parts are less significant than the bigger picture – a more coherent vision for social justice and social mobility. Clegg has dipped in and out of this agenda. He should stick with it.

The Lib Dems have shown an internal discipline that the other parties would not have done had they been in a similar position. (Remember the Maastricht rebels; remember the Blair-Brown hatreds.) Their restraint is, in one respect, admirable. Taken too far, though, it can also suggest an unhealthy ability to cling on to baubles that accompany political power. Compromise is good as long as comfort does not dull the senses or quell the anger that is the lifeblood of radical politics.

The Lib Dems have been far too bashful. Largely untainted by the bankers' scandals, they could and should be leading the way on radical reform. The proposals in the Vickers report were a step in the right direction, but they are far too mild and slow to take effect, reinforcing the legitimate view that all governments – Labour and Conservative – are subservient to the wealthy. This is an area that Clegg should have been crawling all over from the start. The brief flurry of collectivist-voluntary endeavour from the Olympics – coinciding with Standard Chartered becoming the latest bank to face allegations of dodgy dealing – should be used to reinforce that message.

Another area where he should be making more noise is the environment. The Tories' attempts to limit the growth of renewable energies should be resisted more noisily.

Ultimately, it comes down to who needs whom most. It is conventional wisdom that the Lib Dems are clinging on because the collapse of the coalition would lead to electoral annihilation. With the shelving of boundary changes, their task becomes marginally less difficult. But who will blink first?

Driven by a born-to-rule mentality, many Conservative MPs feel insulted by the fact that David Cameron failed to win the 2010 general election and that, as a result of their party's poor performance, they have had to work with others. Yet, unless their fortunes improve markedly (and with the economy flatlining, there is no prospect of that for the next year or two), they have nowhere else to go.

They could take the ultimate risk and go to the polls before 2015, but they would run the risk of leaving office as quickly as they assumed it. They could try minority administration, but the stuttering and haggling would be even more frustrating. So they are stuck; and Clegg, ever so politely, should use every opportunity to remind Cameron of this unpalatable truth.

The forthcoming party conference season marks the halfway point in the cycle of this coalition government. This period, which is also likely to include a cabinet reshuffle, is a moment for Clegg to change gear. He should treat both rival parties with equal distance and courtesy. He governs with the Tories but should start preparing for life after 2015 – with either of them.

The less tribal among Ed Miliband's team are already thinking these thoughts, which is a considerable improvement on Labour's arrogance in 2010. Some, however, are talking about a deal only if Vince Cable is in charge. Labour strategists should be reminded they will not be in a position to choose another party's leader.

The prospect of a rapprochement between Labour and Liberals is causing consternation among Tories, as Tim Montgomerie wrote this week on Conservative Home: "We have to win outright next time or we're likely to be out of power."

The Lib Dems have taken the blows, over tuition fees and more. They have lost the opportunity to modernise our moribund constitution. They have kept stumm for the sake of stability, and been accused by the left of treachery and by the right of petulance. Clegg has two and a half years to put a strongly liberal stamp on government as it seeks a path out of the economic mire.

That is a desperately tall order but, as the past two weeks have shown, success comes to those who show muscle and no little guile.