Maybe I should clarify the underlying idea behind those "Fixing the ..." posts, the Baltic invasion scenario and some other blog posts:
First, a very, very foundational point: Military spending in itself has no net value for society. It's government consumption if we ignore the deterrence and defence purpose.
Military R&D doesn't really advance science or civilian technology much any more, that's a thing of the past. Military service is rarely fun, so that's no contribution either. In fact, most economic effects could be had as well if people were instead paid to build homes, then demolish them, build, demolish, rinse repeat.
Second, there's no profit to be made for the society as a whole in military adventures / great power gaming. Individuals and corporations may make profit off this, but not the society as a whole.
Third, the inevitable consequence: Armed services have the primary and almost lone purpose of providing the common good of security against (organised violence) foreign threats. Their business is deterrence and (if this fails) defence.
The conclusion is that spending should be kept to the level required for deterrence and defence.
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Now what's the required level?
The least unlikely threat scenario that justifies military spending is a Russian aggression (and I'm happy with the fact that this is still very unlikely). I think I showed that such a conflict would be very short and quick if there's much military power in the background that would make an aggression disastrous if it lasts longer. Now we should convince them (or keep them convinced) that even a quick invasion scenario doesn't work out well, for this should provide the deterrence that keeps the peace.
So there are three requirements founded in the Russia scenario(s):
(1) Forces that become effective within the first week and deter a quick aggression campaign plan.
(2) Forces that deter a longer aggression campaign plan.
(3) One or several alliance members sustain a nuclear deterrence (U.S., UK and France)
Fourth, we can add a certain 'competence core sustainment' mode for distant alliance members (for long term deterrence and defence option).
Fifth, at least one alliance member (U.S.) has Pacific Ocean allies and territories to keep in mind.
So for European policies I suppose we should be serious about orienting military policy towards deterrence and defence against Russia.
Poland, Lithuania, Latvia, Estonia, Germany, France, Romania, USAREUR, Hungary, Slovakia and Czech Republic should have their armed forces at least partially at a high-enough readiness for a 'first week' phase.
U.S., UK, France, Italy, Spain should have at least part of their air forces at high enough readiness for a 'first week' phase.
U.S., UK and France maintain the nuclear 'umbrella' (France and the UK could downgrade to cheaper systems than SSBNs/SLBMs, though).
Turkey can mind its own business, it's in a hot-enough neighbourhood (that's nevertheless not going to attack Turkey with regular forces) and may need to deploy its armed forces on its borders for national security any time (in addition to its less laudable ongoing de facto war of secession).
The rest of European NATO could follow military designs that are in part focused on territorial defence and in part focused on maintaining military competence* (but then it should really be competence, not obsolescent doctrine). This includes Spain, Portugal, Italy, Greece, Croatia, Belgium, Netherlands, Bulgaria, Norway (much territorial defence) and Denmark (NATO's lock for the Baltic Sea).
Some NATO members could demilitarise altogether, for their contribution would be insignificant anyway and they're not really wealthy (Slovenia, Albania, soon Montenegro).
Iceland is nice to NATO and provides itself as a base for air-sea warfare, and thus it's fair to return to the old arrangement under which the U.S. provides for its defence.
Luxembourg is a similar exception; it's tiny and lends its flag for NATO aircraft - its single battalion army is OK.
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This is the real difference between what I'm proposing and what most commentary on military affairs in Europe is proposing: When I'm writing about a turn towards collective defence against regular military threats, I'm not only proposing to become qualitatively better about it. I'm also stating that we already have the quantity required AND re-orienting towards actual deterrence and defence can and should include cutting unneeded surplus parts, since these cause unjustified expenses.
Such as a German (or Polish) navy; cut this wasteful spending. Forced entry amphibious warfare vehicles; cut them. Fleet replenishment ships; you don't need those if you defend, for you cannot "defend" far from home.** Occupation warfare equipment; scrap it.*** Obsolete hardware that would fail in a clash of 1st class regular armed forces; scrap or replace it.
The usual commentary doesn't propose to cut such unnecessary parts, and it doesn't mention or take into account that the level of spending and manpower is already grossly in favour of European NATO compared to Russia (and even more so with American NATO).
Instead, the usual commentary on a pivot towards defence against Russia prefers bigger budgets, more troops, more new weapon systems. That's probably even more wasteful than the great power games about occupying Muslim countries.
*: One might be tempted to question this for example in regard to Italy; isn't it a maritime power that needs to defend the Southern flank? The question is; against whom? Algeria, Tunisia and Libya are probably not going to be able to pose a regular military threat to Italy for decades to come. Besides, when did an Italian navy ever justify its budget? Italian naval power hardly ever justified its existence post-Lepanto; exceptions in the 20th century were motor torpedo boats, minelayers, minesweepers and submarine chasers. The Italian armed forces could reduce to a mechanised brigade, militias on Sardinia and Sicily, coastal minehunting systems and a few dozen multirole combat aircraft and Italy would be safe even as a neutral country.
By the way, a single budget brigade or two would be fine for maintaining land warfare competence.
**: The British may shriek now, but frankly, it's idiotic to spend billions for the defence of a community of less than 3,000 inhabitants.
***: Or lend it to UN blue helmet missions.