Most postal Diplomacy players come to grips with the concept of the Juggernaut fairly early on in their careers - the notion that a strong Russo-Turkish alliance can just steam-roller over the rest of the board, crushing all beneath their wheels. I suspect that true Juggernauts are far and few between, in that they often break down early in the game if the going gets tough, but the mythology lingers on.
Given that any firm alliance from the outset between any two powers can be very effective in Diplomacy, perhaps it is surprising that a Russo-Turkish alliance should have been honoured with a special name, after all we don_t go around describing firm Anglo-French alliances or Russo-Italian alliances as anything in particular. It is true that if Russia and Turkey can reach a true accord then they have a lot of potential because they can control two of the four corner positions on the board, which means that instead of operating on the usual expanding balloon sort of strategy, they can just march across the board in a single line. In particular, co-operation in Austria can reap quick rewards, especially if Italy has been unwise enough to attack Austria as well.
Starting Up the Juggernaut
What are the hallmarks of a Juggernaut? Well, it is never easy to predict the alliance structure on the board from S01 moves, but insofar as S01 moves mean anything I would expect a Juggernaut to feature Russian moves along the lines of F(Sev)-Rum; A(War)-Gal; A(Mos)-Ukr or StP, while Turkey orders A(Con)-Bul; F(Ank)-Con; and A(Smy)Std or moves to Ank. On the other hand a stand-off over the Black Sea doesn_t exclude the possibility of a Juggernaut, as Russia and Turkey may want to disguise their close co-operation, though F(Sev)-BLA coupled with A(Mos)-Sev probably does.
The first priority for the Juggernaut must be to crack the collection of SC_s in the Balkans and then release the builds necessary to finance Russian expansion in the north and Turkish expansion in the Mediterranean. Even with a determined and co-ordinated Juggernaut, this can be very difficult if it faces a determined Austro-Italian alliance from the first move. The Juggernaut will be in a better position if Austria opens defensively with F(Tri)-Ven or F(Tri)Std and this would be a good goal for initial diplomacy. Indeed, if you can sow enough distrust between Austria and Italy it may not even be hard to achieve. This immediately prevents a second build for Austria and opens up the possibility of a second build for Turkey. In the autumn the choice will be between using A(War) and A(Ukr) to force Galicia or using A(Ukr/Sev) to move to Rum (the fleet moving to BLA if the intention is to head for the Med. or to Sev if otherwise). No doubt the decision will rest to some degree on Italian intentions. Of course if Russia can persuade Italy to attack Austria from the beginning of the game and perhaps even seize Galicia in S01 then the Balkan battle will be almost won already. Russia will only get one build unless he can take possession of Gal in S01 or if he can persuade Germany to allow him to take Sweden. Neither of these are easy to accomplish. Turkey is also probably going to be limited to one build unless there is immediate hostilities between Italy and Austria which allow him to take Greece..
The other challenge for the Juggernaut is to eliminate the threat to the stability of the alliance posed by the southern Russian fleet. This will usually be sent into the Mediterranean via Constantinople, or returned to rot in Sevastopol. The former is more risky for the Turks, but is better in the long term, the latter is less risky but always leaves open the possibility of a Russian stab. A final solution is to somehow connive to disband the Russian fleet.
If Italy is exerting no real pressure on Austria after S01 my preference would be to order A(Smy)-Con; A(Bul) S RUSSIAN A(Ukr)-Rum; F(Rum)-BLA; A(War)-Gal. It is probably better to get an army into Rumania with the possibility of striking into the Balkans in 1902 then making a half-hearted attempt to stop Austria from taking Greece (which Turkey) may well capture in 1902, with Russian assistance to cut supports, providing Italy does not support an AUSTRIAN F(Gre). Of course if the Juggernaut is not facing an Austrian F(Alb) or if Russia took Galicia in S01 then other possibilities open up, but putting an army into Rumania must be a priority.
One possibility not yet discussed is that the Juggernaut will use A(Mos) to move to StP in S01, on the basis that this will assist Russian expansion in the north in 1902. It is certainly true that if Russia has the security of knowing that her southern flank is safe then she can afford to send a second unit north, and it will probably not affect the number of builds gained in 1901. The only downside is that it means that Rum will have to be taken by F(Sev), so there can be no supported attack on Ser or Gal in S02. The best plan is probably to send A(Mos) to the Balkans if it is thought likely that Austria and Italy will co-operate, but if an Italian attack on Austria is expected, then there is probably more to be gained by heading north.
Assuming the Juggernaut carves up the Balkans between them a fair split would be Rum/Bud and Vie for the Russians and Bul/Gre and Tri for the Turks, with Serbia up for negotiation (though in my experience it usually goes to Russia). In order to force ION Turkey will need at least three fleets (possibly four if Italy has Tri or Mar as well as Tun), which means building fleets should be a priority if ION is to be taken by 1903/04. Russia will use her gains to build armies in the north and west and possibly a second northern fleet on StP nc. One reason why Russia often does better out of Juggernauts than Turkey is that her potential for additional builds is so much greater, thanks to the proximity of Scandinavia. Once Turkey has her share of the Balkans she can get no further until she has broken through the ION bottleneck - which is never an easy task - it will usually take at least three fleets and this is not even achievable until A03 at the earliest. As the Juggernaut rolls on it is easy to foresee that Russian can get the momentum to get up to 10 centres by the end of 1904 (Sev, StP, War, Mos, Rum, Vie, Bud, Ser, Swe, Nwy), or possibly more if units are released to attack Germany), whereas Turkey will probably be stuck on 6 or 7. Nevertheless, it is possible that by 1904-1905 the Juggernaut will control over half of the board.
Putting the Brakes On
But it need not be so: any alliance can be stopped. First, it is imperative that any western power suspecting the emergence of a Juggernaut can get Italy on side. If Italy assists (directly or indirectly) with the partition of Austria then she will release the centres that the Juggernaut needs to gain momentum. Even if Italy has attacked Austria from S01, both should be prepared to bury the hatchet if a Juggernaut is on the cards. Of course it may be very hard to persuade Italy of the sense of such a course of action, as Italy no doubt believes that she has a firm alliance with Russia and that they will both move on Turkey once Austria is dealt with - though in practice Russia may be quite content for Turkey and Italy to face each other while Russia seeks gains elsewhere.
If it is too late to do much to prop up Austria, then the only really effective way to hold back the Juggernaut is for either an early resolution to the E/F/G conflict with a firm alliance between the two survivors to hold the Juggernaut back or a three-way E/F/G alliance in which France turns south and puts fleets into the Med. while England and Germany tackle.Scandinavia and central Europe before Russia can acquire the momentum to enable her to thrive. Solid two-way alliances only really prosper when the rest of the board is suspicious of each other and divided - the danger of the Juggernaut for the western powers is that the potential for quick growth if the Balkans falls early on is such that the other powers may not have time to get their act together.
However, just holding a Juggernaut back could mean that the game ends up in a four or five way draw as east faces west over the iron curtain and I would guess that this rarely happens. Experience suggests that if a Juggernaut can be stopped, the it will not take long before one side of the Juggernaut decides to attack his ally instead. In cases where Russia has been left with a Black Sea fleet then it is all too easy for Russia to order F(Sev)-BLA and build A(Sev) in an Autumn season. And once one side of a Juggernaut attacks the other, you can be fairly confident that the Juggernaut is gone for good.
One question worth asking about Juggernauts is "What is in it for Turkey?" Good question. Unless the Italian player is an idiot, a Juggernaut is almost certainly going to favour Russia - who will slip the knife in when Turkey is over-stretched and claim an outright win. Similarly, Turkey must be content with second place or he must stab Russia at the optimum moment. Neither player can afford to leave his back door open, so it is not unusual for some sort of perpetual mutual stand-off to be arranged over Rum or BLA to protect both sides.
The Juggernaut remains a fearsome alliance, but not a very fashionable one. It requires mutual trust early on (something Diplomacy players are not very good at), but once established can do very well indeed, because to be stopped the other players have to take a long-term view (something else Diplomacy players are not very good at!).