Von Kluck was dragged south-east toward the Marne by BEF/French Fifth Army attacks into his left, which he felt compelled to turn and face ( anatural military reaction- it would have taken great nerves to continue east away from the enemy). Also, in part because the other German armies were massing here, lining up to face the French across a line running east-west and facing south. For von Kluck to have continued east would have taken supreme nerves, advancing with both his flanks 'in the air' and refusing what seemed an opportunity to turn the French line. To Von Kluck, in turning, his right faced an undefended Paris, while he kept contact with the rest of the German forces.

Of course, he was then 'gripped' by this south-facing line instead of turning the French flank, and the French were in turn able to drive into his undefended right.

Lanzerac was a casualty of the situation and his bad relationships. Reading about August 1914 in retrospect, it's easy to take a cool analysis. But for those involved, it looked like the unfolding of a massive disaster, the crushing of all France's hopes and plans since 1871: Plan XVII had failed, the German drive appeared unstoppable and every minute counted to stop it.

In this context, Lanrezac's petulance and arrogance completely overshadowed his foresight: nobody was going to say 'thank you' for his early 'pick' of the unfolding situation, what mattered was developing and executing a cohesive plan. By appearing critical and unenthused at every turn, Lanrezac destroyed the confidence of those around him. Lanrezac's negativity affected his staff and headquarters. Regardless of any military brilliance- and he had shown only competence- this situation is intolerable when trying to extricate oneself from a difficult military situation.

Belgium was an excuse for the British to get involved. The August crisis seems to have caught the British leadership off guard. Britain's traditional military posture is to take advantage of continental wars and stay out of continental fighting, but this only works with a balance of forces. Domination of the continent by one power is what the British always sought to avoid, as such a power could then focus on colonies and shut out British trade into Europe. Preventing this was Britain's prime motivating factor.

A similar situation applied in the USA. In all wars, follow the money. By mid-war Britain had borrowed heavily from the US and US factories and financiers were heavily involved in underwriting the British war effort. The Germans were quite influential in trade with south America and this was an area where there was a lot of potential for US companies to take these markets.

It is important to remember that Germany only emerged as a major power recently (viewed from 1914). Russia was threatened by a powerful Germany and had always been in conflict with 'westernised' Austria-Hungary, an empire largely held together by hatred of Russia.

Some sources suggest that war between Germany and England was inevitable. They themselves quote sources from that time period. Yet, the English cabinet went through so much turmoil just to declare war, and if Belgium had not been violated, war might have not even been declared (my own limited understanding). If this was the case, is the belief that war between these two powers was inevitable a false belief?

Just on this question -

British, and previously English, policy has long been to maintain a balance of power on the continent, thus ensuring that no one power held hegemony and would therefore be able to menace their island fortress.

This was the case during the period of Spanish supremacy when England fought the Armada, and during the Napoleonic wars when Britain was again threatened with invasion.

Thereafter, the British sought to prevent a hostile power having control of the channel ports and this would include of course, the ports in the newly created Belgian state. As Gary Sheffield described it, the policy was "to keep the enemy off the counter scarp"

The validity of this policy was demonstrated in the second war, when Britain faced the possibility of an invasion originating anywhere from Norway through to Brest. Not a pleasant situation!

Morever, German foreign policy could fairly be described as catastrophic following the accession of Wilhelm II to the throne. Rejecting British overtures for the Royal Navy to guarantee German imperial possessions in lieu of Germany forgoing a naval rivalry, the Germans did quite the opposite. The began a massive ship building programme directly aimed at challenging the Royal Navy in the North Sea in the hopes that this would compel the British into being amenable to German interests.

How do you think that worked out?

Of course the British were horrified by this and ended their rivalry with the French - their natural enemies since medieval times. As a measure of how seriously the British took the threat, they even made friends with Russia, a country they had been actively fucking over as late as 1905.

The entente allowed the Royal Navy to strip foreign stations of ships and concentrate in home waters.

Now: Britain was pledged to defend the neutrality of Belgium. It was pledged to an alliance with France and Russia. How are they going to not fight?

The point is well made that if the British did not fight in WWI, the likely result would be a hostile, militarist, expansionist, anti-democratic power holding European hegemony and in possesion of the channel ports. Not only would the enemy indeed be on the counter scarp, but Britain would be isolated and, having welched on its allies, deservedly friendless.