The End of Appeasement: Prague and the Polish Guarantee

The Hinge Moment

Munich had transferred the Sudetenland in October 1938. Six months later, on 15 March 1939, German troops marched into Prague and seized what was left of Czechoslovakia. Bohemia and Moravia became a German ‘protectorate’ under Reich administration; Slovakia became a German puppet state under the priest-politician Jozef Tiso. Hitler personally toured Prague Castle that night. The action was unmistakably different from what had gone before. The seized populations were Czech, not German. The principle of self-determination — Hitler’s constant pretext since 1933 — could not be made to fit. Within two weeks British policy had changed.

Key Fact

The end of appeasement came in two weeks. On 15 March 1939 German troops entered Prague. On 17 March Chamberlain’s Birmingham speech publicly turned. On 31 March Britain announced the Polish guarantee. France joined within days, and on 7 April Mussolini invaded Albania.

15 March 1939: Prague

The Czech President Emil Hácha — who had replaced Beneš after Munich — was summoned to Berlin overnight on 14-15 March. Hitler kept him waiting until 1 a.m. and then presented him with the choice: sign acceptance of a German ‘protectorate’ or watch Prague be bombed at dawn. Hácha reportedly suffered a heart attack during the meeting and was kept conscious by injections from Hitler’s personal physician. He signed. German troops entered Prague at 6 a.m. on 15 March. Slovakia, encouraged by Berlin to declare independence the day before, became a satellite state. The whole of Czechoslovakia was gone.

The British Public Turn

In Britain, the public reaction was sharper than anything since 1935. Munich had been welcomed because it had appealed to a principle — self-determination — and avoided war. Prague could not be defended on either ground. The Times, which had backed Munich, turned. Conservative MPs who had cheered Chamberlain in October 1938 now openly questioned the policy. Lord Halifax, who as Foreign Secretary had accepted Anschluss with regret in March 1938, told Chamberlain bluntly that the policy had run out. Chamberlain’s personal credibility was on the line. On 17 March, in a speech at Birmingham marking his seventieth birthday, he made the public turn. Britain, he said, would resist any further German moves toward European domination.

The Birmingham speech of 17 March 1939 is sometimes called the moment Chamberlain ‘abandoned appeasement’. The reality is more nuanced. Chamberlain still hoped to avoid war, but he now publicly accepted that Hitler could not be trusted to honour an agreement — the central premise of Munich. The shift from negotiation to deterrence followed within two weeks. The policy that had defined British foreign policy since 1937 was over in everything but name.

31 March 1939: The Polish Guarantee

Hitler had begun openly pressing Poland for the return of Danzig — the Free City under League administration — and for an extraterritorial corridor across Polish territory linking Germany to East Prussia. Poland refused. On 31 March 1939 Chamberlain told the House of Commons that Britain would lend Poland ‘all support in their power’ in the event of any threat to Polish independence. France joined the guarantee within days. Greece and Romania received similar guarantees in April. The strategic shift was complete: Britain and France had moved from negotiation to deterrence.

Historians have long argued over whether the guarantee was militarily credible. Britain and France had no direct way of defending Poland; their best hope of relieving German pressure was a Western Front offensive that neither was militarily ready to launch. The guarantee made political sense as a deterrent — signalling to Hitler that any Polish move would mean war — but it could not stop a German invasion in practice. The guarantee’s real purpose was therefore to deter, not to defend. When Hitler called the bluff in September 1939, Britain and France honoured their promise but could not save Poland.

Conscription and Mussolini in Albania

In April 1939 Britain introduced peacetime conscription — the first time outside a major war — signalling to Berlin that the rearmament effort had moved into a new phase, with men as well as money committed to the coming confrontation. On 7 April 1939 Mussolini opportunistically invaded Albania, taking advantage of European attention focused on Poland. The Italian move did not provoke a major Allied response — Britain and France were focused on the German threat — but it confirmed that the Axis powers were now acting in coordination, and prompted further British guarantees to Greece and Romania later in the month to deter any Italian move toward the Balkans.