How was the WWI stalemate broken?

Here, I am asking specifically about the tactial and strategic reasons why the stalemate on the Western front in WWI was broken. I am not asking how WWII was different from WWI but rather what happened during WWI that made it go from a stalemate to a non-stalemate.

Here is a summary of the reasons for the stalemate:
The short of it is that it was safer and more effective to defend than attack. This is pretty much what a stalemate is and so is only helpful if we go into further detail.
Strategic, geographic:
On the Western front, there was a high density of troops so that all of the Western front was trenched up. This left less room for manoeuvre. This meant that factions were mainly restricted to frontal assaults.

Machineguns and artillery made attacking fixed positions very deadly for the attacker.
Machineguns in WWI were difficult to use offensively because of their weight but could easily be used defensively.
Artillery is a lot less effective against dug in defender than attackers crossing the no man’s land.

The use of artillery by the attacker was served as a warning to the defender as to where the next attack was going to be. It also made moving over the terrain more difficult.

Logistics and communications:
The attacker could not exploit its tactical successes faster than the defender could reinforce and counterattack.
The state of communications made it so that it was more difficult for the attacker to coordinate than for the defender. The attacker also had a greater need to coordinate.

Air reconnaissance made it difficult to build up a large force without being detected and the defender massing troops in the same area.

It was a combination of things. Largely it was just that Germany was physically and morally exhausted by 1918, even with the Russians out of the war. The introduction of American troops, although numerically minor, gave the prospect of being able to draw the last drop of blood from the German war effort.

To the extent that tactics or strategies changed, it was the following: the first generation of tanks allowed some success in overrunning trench positions; the “creeping barrage” artillery tactic allowed better artillery support of an attack; and trench storming tactics evolved including the use of combat shotguns, the very first submachine guns, and automatic rifles, which gave the attacker better weapons in the tight confines of trench fighting.

A while back I started a thread called WW1 refought 1918 style, postulating what might have been different if the belligerents could have somehow instantly acquired four years bitter expericence in 1914.

The Allies had more men and more material, and the U-boat menace was under control. The Germans almost managed it through developing tactics that subverted the challenges of positional warfare; but it was still enormously costly.

The Germans made the mistake of having no overall strategic plan and so they attacked in three different directions at three different times, allowing the Allies to move their troops around to counter. When the Germans finally suspended attacks, the Hundred Days offensive opened which was a general attack all along the entire front.

I must highly recommend “Battle Tactics:Trench Warfare” by Stephen Bull, an exhaustive account of weaponry and tactics in WW1. To summarize from an earlier thread, the common trench attack method in 1915-17 was to bomb an intended battlefield several days before the attack and then to launch waves of infantry at the enemy positions. This was basically firepower versus manpower, and firepower almost always won out.
What happened in 1918? Tactics shifted to firepower versus firepower, and the attacks became much less regimented. The pre-attack artillery fire was shortened to hours, but became far more intense. When the attack finally came, infantry were not the first out the trench; they were proceeded by tanks, mortars, and light machine guns. Plus, the attacks were coordinated so that when one section of a fighting was moving forward the other helped cover it with gunfire. This was a huge advance over the Somme-era "hope all the defenders got killed so we can advance unopposed’. Another major advance was orders of attack were simplified and decentralized. Advances in communications allowed changes in artillery fire to be made on the battlefield, instead of relying on plans done days before the attack. If one unit was far more successful than the others, battle orders could be quickly refined to exploit their success.
And finally, generals began to realize aiming for steady pressure on the battlefield was far more effective than gambling on a single breakthrough. It was clear after the first day of the Somme the hoped breakthrough wasn’t going to happen. Then why did the battle last for four months? Because the battle had taken so long to plan that you couldn’t just think up a new offensive. In contrast, when an advance began to stall after a few days in 1918 the generals would usually launch an attack on a new sector within days.

For all the advances in tactics and equipment, the biggest factor, as Lumpy points out, was accumulated attrition. The Allies still had the men and munitions to mount multiple offensives (plus the prospect of millions more American troops for 1919), the Germans had no reserves left.

In 1915-17, German tactics had been to aggressively counterattack any Allied advances, thus maintaining the line in place. By the autumn of 1918, with no fresh troops for counterattacks, all they could do if the front line was broken was fall back and try to establish a new line, then fall back again when that was broken - and so the front line began to head towards Germany.

On top of that, the German economy was crumbling under 4 years of blockade and the German soldiers increasingly believed that the war was hopeless. Exhaustion and demoralisation led to a decline in effectiveness, which led to defeats which fed straight back into more exhaustion and demoralisation. No-one wants to die in a war that’s already lost; by October 1918 the German Army was approaching mutiny.

It’s worth noting that in the Battle of the Somme in 1916 - the archetypical slaughter-by-machinegun of WW1 legend - total losses were about 600,000 Allied, 450,000 German - roughly 4:3 in favour of the defender. In the Battle of Passchendaele in 1917 - the archetypical mudsoaked massacre organised by incompetent out-of-touch generals, losses appear to have been about even. In the Meuse-Argonne offensive in the last months of the war, total losses were around 180,000 Allied, 120,000 German - 3:2 in favour of the defender. In the 1918 offensives, the attackers still lost much more heavily than the defenders (unless they could break the enemy’s morale or cohesion and capture large numbers of prisoners). The difference was that the Germans no longer had the warm bodies to throw in the meatgrinder, and without them they couldn’t hold the line.

There was also an economic breakdown in Germany. Germany was isolated by a blockade. It takes a while but eventually they began running out of resources. The Allies had access to world markets and more credit so their economy could outlast the Germans.

Another factor was that Germany had to keep fighting at the same level throughout the war. The Allies were able to play tag team. Germany had to fight France, then Russia, then England, then Italy, then the United States.

Everyone here is making the same mistake in assuming it was the allies that broke the stalemate in WW1.

They did not.

The Germans broke the stalemate during march 1918 during the Kaiserschlact offensive.

They did it through new tactics. Stormtrooper tactics, the predecessor of WW2’s Blitzkrieg tactics. Now obviously these new tactics didn’t lead to German victory, but it did break the stalemate. Significant amounts of territory were captured in a relatively short amount of time.

No the did not. The Germans reintroduced manoveur warfare to the front. Said warfare admittedly came very close to achieving a breakthrough and ending the stalemate, but ultimately it failed like all previous offensivesand the stalemate remained. THe stalemate was broken during the Hundered Days, principally by the British and Empires Armies. Operation Michael did cost the Germans about as many casualties that the British had suffered at the Somme and Paschendale, combined and greatly hampered their ability to deal with the 100 days. So in that sense, yes the Germans did break the stalemate.

The US’s vast resources played a part in both World Wars. By the time we entered WWI Britain and Germany both had expended too many resources. Now, there’s a fresh fighter to deal with.

Think of a Boxing Match. If in the 9th round one of the tired fighters sits down and the new guy takes over. How long will the other tired guy last?

It was even worse in WWI because Germany was fighting the Brits and the US.

It was specifically mentioned in post #3.
They did it through new tactics. Stormtrooper tactics, the predecessor of WW2’s Blitzkrieg tactics. Now obviously these new tactics didn’t lead to German victory, but it did break the stalemate. Significant amounts of territory were captured in a relatively short amount of time.

And lost in an equally short time. As I said in the other thread, the big problem with offensives in WWI was not that they couldn’t break through the trenchlines on occasion, it’s that they couldn’t exploit that breakthrough. What little cavalry was left couldn’t transit the moonscape that was no man’s land, and the infantry that did break through were out of communications with their own side, and frequently out of supplies and reserves as well. Whereas the defender’s reserves were fresh and right there, so invariably pushed the exhausted attackers back to the start line.

The difference with the Hundred Days offensive was a combination of factors that came into play at the same time: the Allies, in particular the British, finally cracked the technique of timed attacks behind rolling barrages, AND fed reserves in to push on with the attacks after the first wave of attackers were spent, AND maintained communications with the attackers using planes, signals, and IIRC the first portable radios, AND had superior numbers due to 1/ German losses in Operation Michael and 2/ the arriving Americans, AND they were following up the German retreat from Michael and didn’t let them retire to their trenches and regroup, AND used tanks to exploit … there’s probably more I’m not thinking of right now but I think the point is made - there was no one factor, pretty much all these were required to break the stalemate.

It’s true to say that the prospect of large numbers of fresh US troops arriving pushed the Germans into their last, and most successful, attack, Operation Michael, the eventual failure of which contributed greatly to the end of the war a few months later. The actual numbers and effect of US troops at the time was quite small.

Whereas in WWII they were only fighting the Brits, the US and the USSR. What?

Actually, the Germans were just imitating Russian tactics. It was the Brusilov Offensive that first used “shock trooper” tactics.

These tactics led to the Russians gaining a lot of territory in 1916 just as they led to the Germans gaining a lot of territory in 1918. But ultimately neither offensive was enough to break the strategic stalemate and win the war.

There was another example here of the German high command shooting itself in the foot.

The German plan had been to send all its available troops to the eastern front and knock Russia out of the war. And this plan worked. The Germans won a major offensive and Russia asked for terms.

Then the Germans got stupid. The plan had been to beat Russia quickly and get the troops back to the western front so they could knock France out as well and win the war. This was the ultimate goal. But the Germans lost sight of this.

They should have negotiated a quick treaty with Russia and got their troops on the move. Instead Germany asked for incredibly severe terms (much more severe that the terms Germany would be asked to accept at Versailles). The terms were so severe that Russia refused to accept them and tried to start fighting again. The Germans had to launch another major offensive to drive the Russians into signing the treaty.

The result of this was the German troop movement from the east to the west was delayed for three months. If Germany had been wiser they would have offered Russia a relatively easy treaty that they would have accepted initially. And that would have allowed Germany to launch its 1918 offensive in the west several weeks earlier, before any significant amount of new American troops had arrived at the front. With that advantage Germany might have broken the French and British armies in 1918 and won the war.

Operation Michael was launched on 21 March 1918. I rather doubt it could have been launched “several weeks earlier”, as that would be in the dead of winter.

The Masurian Lake offensive was launched in February 1915. The Verdun offensive was launched in February 1916. The Ukrainian offensive I mentioned above was launched in February 1918.

So an earlier offensive would have been possible if the troops had been there for it.

Another thing is that by 1918 many of the German allies were floundering and that relieved pressure on the other fronts for the Allies, especially Britain. Several divisions worth of troops were shipped by the British from the Middle East just before Operation Michael.

The introduction of American troops certainly turned the tide, as all have mentioned. Additionally, the adamant refusal by Pershing to allow American troops to merely become replacements and additional fodder for entrenched positions probably hastened the war’s end.

Oddly enough what finally caused the Germans to be hopelessly lost was the Italians, of all people. After losing almost every battle for four years, they finally bled the Austrians dry and their empire broke up. After the Austrians were knocked out of the battle, the Germans would not only be doomed to a (fairly) slow retreat backward toward the homeland, but their southern front would be vulnerable as well even if they managed to stabilize the Western front.

When Russia left the war in 3/18 Germany’s strategic position was drastically altered
in its own favor: what had been a two front war was now a one front war. Consequently,
Germany was able to transfer several 100,000 soldiers from the Eastern front to other
sectors; it may even have had a million more.

Germany began launching massive attacks in France against the French and British
positions shortly after the Russian peace. It was able to achieve some significant
but not decisive breakthroughs, culminating in the 2nd Battle of the Marne in 7/18.
After this last German offensive was repulsed, France, Britain and the US had the
initiative, and drove the Germans back until their lines were strained to the breaking
point, and they had to sue for peace.

I am not aware of any radical tactical innovations employed by the Germans in their
1918 Western offensive. Any such tactics were ultimately futile against defenses still
appear having the upper hand. Success of the Allied counter offensive was largely due
to attrition suffered by Germany in the prior several months, and by the mounting US
contribution which reached 29 fighting divisions in the last two months of fighting.