Actually, the Maginot Line was a good idea

YouTube channel Historigraph has a pretty great primer on this concept that you can check out above, but we're going to go over his arguments and that of historians below.

The purpose of the Maginot Line was to secure France's border with German so well that, even accounting for Germany's much larger population and birth rate, no attack over the border could succeed. This was to be achieved with strong defenses and massive concentrations of artillery.

And so it was constructed with thick concrete — reaching 12-feet thick in the most secure bunkers — and artillery and machine guns with overlapping fields of fire along a 280-mile front. The defenses were so imposing that military planners counted on second-rate troops to man them in case of a war.

But why would French planners place second-rate troops on the border with their greatest nemesis, even if they had great defenses? Because the French knew that Germany wasn't limited to attacking over its shared border with France. And the military wanted its best troops available to fortify the less built-up grasslands in Belgium.

France had a deal with Belgium that, in case of a likely or actual invasion by a foreign army, would allow French troops to operate on Belgian soil. The plan was for the best French divisions to form a battle line with their Belgian counterparts along the River Meuse and Albert Canal.

The River Meuse was a great, natural bit of terrain for defenders that, when combined with the Albert Canal, would allow Belgian and French forces to hold back an attacking army for an extended time. It had seen fighting in World War I, and it always went bad for the attacker.

Nearly all of France's tanks and most of her best troops would man this barrier and prevent a German invasion from the north. But, German forces would be forced to come against this defensive line because the only alternative was attacking against the Maginot Line — suicide.

But there were two flaws in France's assumptions that wouldn't be revealed until too late. The first was that Belgium was a neutral state in Europe prior to 1914. When Belgium was formed in 1830, it was as a neutral buffer state and all the major European powers gave some guarantee towards that neutrality. Most of the pledges stopped short of saying they would necessarily defend Belgium if it were invaded, but that was the general understanding.

So, Belgium was not actuallysuper comfortable with being an ally of a major European power in case of war. The country preferred neutrality instead. The other big problem was that Belgium in 1936 had a young and inexperienced king who headed a small military. King Leopold III needed strong guarantees of French resolve.

And so when Germany violated the Treaty of Versailles by moving their own troops into the Rhineland, German territory that was off limits to its military under the terms that ended World War I, Leopold III became scared. Rather than count on France to hold up its end of the bargain, he broke the pact with France and reasserted Belgian neutrality.

And that is what made the Maginot Line suddenly much less useful. Sure, it would still force the Germans to go around it, allowing 943 miles of border to be guarded with lower-tier troops. But France now had hundreds of miles of border, most of it bare plains, that were guarded by nothing but Belgian hopes and dreams.

Hitler invaded and France raced to set up a defensive line as deep into Belgium as they could. But the Germans broke through Belgian defenses even more quickly than anyone could have guessed, partially because the Belgians had under-supplied one of the world's best forts.

Fort Eban-Emael was the anchor of defenses on the Albert Canal, but Germany landed a bare 87 paratroopers on top of the fort, which was built into a hill, and captured it. The defenders had machine guns and artillery that could sweep the top of the hill, but their weapons maintenance was shoddy and the artillery lacked the canister shot that would have been most effective.

The fort fell in the first day, and the three bridges it guarded were soon lost as well. The Germans swept east and finally encountered the French digging in on the River Dyle. And here was where French armored doctrine failed. French tanks were only slightly outnumbered, but were committed to battle piecemeal while German armor was formed into strong columns capable of forcing opening in French lines and then exploiting them.

And the French also underestimated the ability of modern tanks to navigate the tough terrain of the Ardennes Forest, failing to send either a counterattack or bombers to the forest despite multiple reports that German armor was making its way through.

And so, the Maginot Line stood, strong and proud and funneling German troops north just like it was supposed to. The Maginot Line allowed France to choose its ground. But because of diplomatic missteps and a failure by French generals to understand the changing role of the tank, the defensive lines to the north failed.

The general argument against the Maginot Line is that the money should have spent on tanks, planes, and other modern equipment instead, but those were the exact assets which France failed to properly employ.

Today, fixed defenses are out of vogue as strategic bombing and bunker busters have made them nearly impossible to man for long. But they had one last hurrah in them in the Battle of France — if only their successes had been combined with good combined arms maneuvering.