So what might such a narrative look like? Maybe a little overwrought, but here's an attempt...
At the last election, Nick Clegg was a star: providing clarity at a time of great doubt, idolised, a great shining hope. Of course, stars fall; they all do. The question is: then what?
Remember that in 2010, Nick Clegg alone lit up the hearts and minds of the country when he said firmly that the economy desperately needed sorting, that the banks shouldn't be allowed to get away with it, and that sleaze had to stop. "I agree with Nick" the leaders of Labour and the Conservatives had to admit. So much so, that when the people spoke on election day in 2010, David Cameron realized that he nee ded Nick's help. Nick Clegg's star was shining bright, in the country's dark economic times.
Then, in 2011, the star fell.
The dreadful deficit needed tough, unpopular decisions. It meant having to compromise with David Cameron on dearly held liberal policies like free university tuition. Nick won a deal that meant no fees until graduates were earning a decent wage. But people didn't care, because their star had fallen.
Nick ensured that schools in deprived areas got more, rather than less. He ensured a level playing field for cleaner, cheaper, safer energy. He built bridges with our allies abroad, instead of riling them up. But still people didn't care, because their star had fallen.
Coalition with the Conservatives meant constant tough negotiations, to make every bill more liberal, more fair, and more compassionate than it would otherwise have been. Everyone now acknowledges that it was only thanks to LibDem parliamentarians that the NHS changes originally planned never happened. Instead, the NHS is now protected from the excessive competition that Labour let in and that the Conservatives wanted more of. But people didn't care, because their star had fallen.
So now, in 2015, where is that star?
The economy is on the right path again, but the task is not finished. The country needs more jobs. We need to give more powers to our cities and counties to kickstart local economies, to sort out endemic housing issues, to take advantage of green opportunities, to support your hospitals and schools...
That remote, idolised star from 2010 is no more. But in 2015 Nick Clegg and the LibDems offer a guiding star. Lighting a way between cold hard corporatism on the one hand, and overweight statism on the other. Lighting a route to a healthy, growing, happy country.
The more LibDems in Parliament, the more powerful that liberal light.