You would think that spending time in America and thereby enjoying a ringside seat as the Republican party leaps off a cliff would give any British conservative cause to give thanks for the Tory party's essential moderation. Not so with dear old Tim Montgomerie, however, who appears to have gone off his rocker and resigned from the party.

Now there is something to be said for hacks not being members of any party and in that respect Tim's decision to abandon the Tory ship is a case of better-late-than-never. On the other hand, this is a man who once served as Iain Duncan Smith's chief-of-staff and there is something quixotic about surviving that experience only to abandon ship when the party is actually in government and likely to remain so for the foreseeable future.

Still, we've all had weeks when we've struggled to think of a column.

Tim is, I should say, a thoroughly decent cove and he was kind enough to punt some work my way back when he was comment editor of The Times. Moreover, as the founder of ConservativeHome he has been more important to the modern Conservative party than most members of the cabinet. His latest project, The Good Right, is important and necessary and thoroughly to be recommended. He has done a lot for his party and the wider conservative movement.

Be that as it may, Tim's reasons for resigning from the party whose cause he has advocated for nearly 30 years are an interesting reminder that all political parties forever teeter on the edge of madness. Plunging into the abyss is always an option.

Madness? Yes, really. Ordinary people - that is, people who retain their faculties and a sense of perspective and proportion - do not write or think things like 'nothing registers more strongly on the social injustice front than recommending staying in the EU'. There are, as everyone knows, plenty of things wrong with the EU and it is is also plainly the case that none of those things are going to be fixed any time soon but, nonetheless and even if you allow for the harshness of EU orthodoxy in Greece, Spain and Italy, the idea it is, in a British context, the fount of 'social injustice' would be hilarious if there weren't the nagging suspicion that, by god, these people actually mean this stuff.

Nor is the rest of Tim's critique terribly persuasive. I mean, of course he's right to observe that this government has achieved less than it might have but that, he seems to forget, is the case with every government. And, he might also remember, this is a good thing. Governments should fail; a government that gets and does everything it wants is a terrifying thought. Mercifully, events and circumstances impose failure upon government, trimming their wings and clipping their ambitions. This should be considered a virtue, not a vice.

Yes, George Osborne has broken all his financial promises. He has been given greater credit for his intentions than his performance. The deficit has not been eliminated and, as Tim complains, this will have consequences for years to come. But you can't sensibly complain about this - and it is an entirely reasonable complaint - and then write 'The national debt is up by more than 50 per cent, but this hasn’t seen our armed forces rebuilt.' So - and correct me if I'm mistaken here - spending on the things I dislike is bad but spending on the things I like is virtuous? I want my sweets but you can't have yours. OK!

It is all very well and good posing as an iron-clad deficit hawk but what are you actually proposing to cut? The education budget? No. The health budget? No. Pensions? Come on. Even the great cause of welfare reform pits the reformers against the Treasury since the moral argument for welfare reform accepts that, at least in the short term, spending might have to rise if longer-term goals are to be reached.

Besides, if - and Tim, it should be said, is serious about these things - inequality and social injustice is your particular thing then honesty should compel you to accept that the people who depend most on government services are the poor. The wealthiest 30 percent of citizens need much less from government than the poorest. Lopping another £100 billion off government spending is bound to have a greater impact on the poorest third of citizens than the richest.

It cannot be said too frequently that the Tory party's biggest difficulty is the perception that it is the party for the rich. This is its original sin. Nor is this always an unfair perception. Consider how exercised the party is by the rate of tax paid by millionaires. Recall, too, how George Osborne has upset large chunks of the party by reforming the buy-to-let sector and trimming the pension advantages hitherto enjoyed by the very wealthy. Every move that might indicate we're all in it together has been fiercely resisted by a significant part of the Tory base.

That base is changing, however. (Thank you Mr Corbyn!) Tim complains however that, 'A radical transformation of the Conservative party is under way. The Tories who defected to Ukip before the last election were replaced by the kind of people who voted Liberal Democrat at the previous four elections.' Well, thank heavens for that. Out with the misanthropes, cranks, and pessimists and In with the sane and the moderate! And this is a problem? Far from it.

The problem true believers have is that the British people are not true believers. They are moderates, instinctively suspicious of radicals. They believe in Stoke Poges, not a New Jerusalem. Mere managerialism does not inspire newspaper columnists but a government modest enough to recognise it can only muddle through, improving a few matters here and there, is greatly preferable to one that thinks it can change everything.

That includes the damn european question. It should be an axiomatic part of Tory DNA that a known known is preferable to an unknown known, let alone an unknown unknown. It might not be splendid or even altogether desirable but managing, or coping, with an inadequate status quo is the job, even the point, of government. The purity of certainty is for radicals and, therefore, utterly suspicious.

That's the problem with UKIP, you see. And it is also the problem with people, like I am afraid Tim, who bleat about Britain being 'chained' to Brussels. Ordinary people recognise that this is a timid form of bondage. So milquetoast, indeed, that dressing like this wouldn't permit entry to any self-respecting fetish party.

The point of David Cameron is that he doesn't believe in anything very much. In this respect he is ideally suited to be Prime Minister of this country because, on the whole, the British people do not believe in anything very much either. They crave a measure of reassurance and certainty and would like their government to be as unobtrusive as it can be. Modest and incremental improvement, delivered by the kinds of people who seem as though they are the right sort of people to be in government, is what they want.

This is both a small and a large thing; small because it recognises a measure of reality but large because it demands a modesty of a kind governments struggle to remember. It is no accident. I think, that this government gets into trouble whenever it moves off the centre ground and into ideological territory.

Cameron, however, is not a zealot. This, again, is his great strength. It disappoints pundits and fanatics who bore on about willpower and strength and vision and all the rest of it. But just as American conservatives are forever banging on about Ronald bloody Reagan so their British counterparts who hark back to the halcyon days of Margaret Thatcher's premiership are deluding themselves. Now is not then and the challenges today's politicians must face are not those that were faced back then. 2016 is to 1979 as 1979 was to 1943. It is time, you know, to move on.

Tim signs off by saying 'I'm just glad Mrs Thatcher cannot see what her party has become'. Well, I'm afraid the old dear went off her rocker by the end of her time in office and it was, in large part, the legacy of that nonsense that kept the Tory party out of power for so many years. There remain plenty of people, it seems, who prefer the purity of opposition to the compromises of office. This, it should also be noted, is a madness afflicting the Labour party right now. But the Conservative party exists to be in power. Otherwise there is no point to it.

And the value of being in power does not wholly depend on what you do with it. Part of the point of the Tories being in power is that their being in office means other people are not. That has a value in and of itself too. Because however bad or disappointing the Tories may be, it should always be remembered that things could be even worse.