How swiftly a traumatic event can fade into memory. The Eastleigh by-election is fully recorded on Wikipedia, and is unlikely to be missed out of any history books on the Coalition years, but how often do you hear it discussed in political circles? For some reason – presumably that of collective comfort – it has been stuffed and put in an out of the way display cabinet marked “by-elections”, in the hope that its memory will become less painful as the moths pick at it.

That is a rather dangerous topic to neglect. For the Conservative Party is yet to really face and overcome the troubling problems which Eastleigh raised. Faced with a by-election that should have been winnable, we instead found that the constituency had become the party’s Room 101. The nightmare contained within it was the almost complete withering away of the local grassroots – and the result was not only the failure to gain a new MP but to let UKIP gain further momentum with a second place showing.

There were three truly frightening aspects of the Eastleigh Problem. First, the secret knowledge most Tories carried within them that such an atrophy was far from rare (at the time, the party still had not released its official membership figures, which made the fear worse). Second, the disturbing degree to which the problem appeared to have taken the party by surprise. Third, the continued failure of the centre to recognise the importance of the party’s associations and members.

Over a century and a half, the Conservative Party has built institutions on top of its grassroots base – philosophers, policy experts, technocrats, logistical specialists, copywriters, spinners, candidates, peers of the realm and so on. That’s all to the good – as UKIP are currently learning, it’s the addition of that professional function to assist supporters on the ground that really propels you into political contention.

But when an organisation’s grassroots decline, those lingering functions of its centre serve to mask the scale of the problem. Campaigns are launched, pamphlets written, leaflets sent out, speeches made – but more and more it becomes a mere imitation of life.

Eventually that underlying reality is exposed by a real test. An army, equipped with generals, vehicles, radio operators, cooks, artillery pieces and ammunition may look and sound very impressive as it rolls out to the front, but if its fighting troops, the tip of the spear, aren’t there then it will swiftly be found out in combat.

For the Conservatives, that embarrassing skirmish was Eastleigh. Painful as it was at the time, we’re fortunate to have received a warning in microcosm from one of the seats where things are at their worst, rather than to have suffered a larger collapse in a bigger, later battle. The key is how we and our party respond to it.

There have been some practical reactions to the experience. As Andrew Gimson reports today from his visit to Newark, and as I wrote last week, the by-election machine is now in large part a conveyor belt, delivering MPs, Cabinet ministers, candidates and peers to the battlefront. Evidently there is a commitment that we should not be caught short of troops again.

Similarly, as Mark Clarke wrote yesterday there are new organisations like RoadTrip2015, which busses in scores or hundreds of activists into target seats and by-elections to deliver huge amounts of literature and knock large numbers of doors.

More broadly, Grant Shapps has founded Team 2015, a new arm of the party which signs up supporters for free and allocates them to campaign in their nearest 40/40 target seat.

Each of these is an improvement on Eastleigh – even planning ahead to ship in loads of MPs is better than realising at the last minute that if you don’t then there won’t be anyone to go canvassing. But it isn’t a sustainable solution. These shock troops, deployed to plug gaps in the line or to fight particularly difficult battles one by one, are a useful addition in themselves – but they’re no substitute for a mass, grassroots movement.

You cannot use reserves to fight on every front – surviving a by-election is one thing, winning a General Election is quite another.

The current schemes to build up targeted activist groups should certainly continue – at the moment they are all that stands between us and a potential repetition of Easteigh – but the Conservative party should be doing much more to rebuild its wider grassroots. Some ideas to do so were floated in a discussion on this very topic at last Saturday’s ConservativeHome conference.

Of course, getting the right message and the best messengers is a large part of making our party attractive again – we’ve suggested various ways to do so in the last couple of days. But we also need the right model of membership to make it as easy as possible to join, and to get the most out of those who do.

As Douglas Carswell laid out on Saturday, we are currently hawking a rigid, outdated form of membership to punters who live in a flexible, convenient world. We are, as he put it, acting like HMV in an age of Spotify. It isn’t just rhetoric, either – Carswell regularly packs hundreds of people into fish and chip nights in his constituency, and many of them evangelise on his behalf to their friends and neighbours.

The basic membership model is often assumed to be the only one because “it’s always been done that way”. But consider it from the buyer’s point of view.

What are we asking? That you ignore popular suspicion and dislike of political parties to spend your spare time going out in all weathers, pushing leaflets through doors and talking to people who may very possibly then be rude to you for doing so.

What are you earning for undergoing this experience? Well, actually we ask you to pay to do it.

It’s a model perfectly targeted at the masochist market, but so far sales are proving to be quite limited.

When it is the political party which needs people’s time and effort, why does the party charge them to contribute? Why not have a system of ‘buying’ your membership by doing things – by leafleting, canvassing, envelope-stuffing and so on? In my ward, as in thousands of others across the country, leaflets are far easier to come by than people to deliver them – we’d rather have an extra activist than an extra £25 to pay for literature.

As well as reducing the price of becoming a grassroots activist, we also need to increase the reward. There are two ways to do this.

The first is increasing the power and representation of the membership. While we have a democratic system for choosing our leader, the rights of members and associations have otherwise been severely eroded in recent decades.

“Get what you’re given” isn’t a successful message in business, and it isn’t a successful message in politics, either – there ought to be radical reforms to the way the grassroots feed into policy, candidate selection and party management. Doing so would be a useful step in retaining our existing members and improving the offer for those who might consider joining, even leaving aside the wider electoral benefits of making the party more in touch with the nation.

The second, broader step is to build grassroots movements specifically targeted at delivering policy goals.

People involved in politics often talk of the 1950s as a halcyon age of grassroots activism. In many ways it was, but we all too often neglect the decades that came before it. Between the wars, and before the First World War, there were mass, issue-based political movements which huge numbers of ordinary people joined in order to make a difference on particular policy areas (in the case of women, many joined to change politics even though they didn’t yet have the vote). Free trade, temperance and a host of other issues had their own pressure groups, often allied to particular parties.

We should seek to build the modern equivalents of such movements, targeted at slowly overcoming the distrust and disappointment which has poisoned the relationship between political parties and voters. Politics is ideological, but it should also be transactional – you vote for someone and in return you get what you want, be it on a matter which you think is right, a matter which benefits you, or both. People aren’t apathetic, they strongly care about all sorts of issues, but party politics has lost touch with their enthusiasm and refused to offer a trustworthy way for them to act on it.

Robert Halfon’s successful campaign on fuel duty was the economically right, socially just thing to do, and it was a vote-winning initiative. Imagine if we had built a free, simple organisation alongside the Conservative Party specifically targeted at delivering it. If you want your fuel duty cut, you should vote Conservative – sign up here, click here to tell your friends, read our next email to see how you can do more to help an MP get elected who will vote to cut your bill at the pumps.

The Scottish Conservatives have been experimenting with just such an approach, setting up Conservative Friends of the Union as a route for people to give their time and support to save something they care strongly about. As Ruth Davidson MSP wrote yesterday, it’s working – the Tory vote North of the Border went up last week, flying in the face of all the trends.

It is a simple concept, but I won’t pretend it’s an easy one. It will take time to rebuild our grassroots, time to change people’s expectations of us, and time to alter Westminster’s expectations of how politics should work. But it must be done.