Hitler's voyage into Western Europe was a side note, distracting him from his larger goals. The alliance of Austria into an "Anschluss", the incorporation of the Sudentenland, and invasion of Czechslovakia and Poland were the initial steps of Germany's foreign policy. Only the Nazi-Soviet pact of 1939 prevented Hitler from launching an all-out invasion of the Soviet Union prior to Operation Barbarossa in 1941. It was only the military necessity of crushing Allied resistance that drove Hitler to invade the Low Countries in France in 1940. Clearly, Hitler's motivation lay to the east of Germany. As Early as 1924, Hitler espoused a belief that Germany needed a "Lebensraum", or Living Space, and that this could only be accomplished through lands to the East. As his publication Mein Kampf stated:

We National Socialists must hold unflinchingly to our aim in foreign policy, namely, to secure for the German people the land and soil to which they are entitled on this Earth…If we speak of soil in Europe today, we can primarily have in mind only Russia and her vassal states…may the adherents of our movement never forget this.

This desire for Lebensraum was the ideological motivation for Hitler's aggression, but he had additional reasons to avoid going to war with Great Britain. In France, Hitler saw himself as a liberator in initiating a strong Europe in defense of Bolshevism. The government of France was given much more leeway to rule than the occupied nations of Poland or Czechslovakia, nor was their the widespread raping and pillaging of earlier Wehrmacht campaigns. Hitler's despised the French for their terrible treatment of Germany at Versailles, but Hitler wanted a subjugated France, not a destroyed one.

Furthermore, the quick capture of France surprised even the German army. Very few preparations had been made for any overseas invasion. The German Navy lacked the effectiveness and military power of the Royal Navy, and the troops that were saved at Dunkirk remained a potent force. It was under these circumstances that Hitler hoped to achieve a peace with England in 1940, and avoid going to all out war, unless it was necessary.

In England, however, the situation appeared quite different. After the tremendous failures of appeasement, the fiascoes in the defense of Norway, the quick fall of the Low Countries, and the apparent suffocation of Western Europe, the tenure of Neville Chamberlain as Prime Minister came to an end. The Parliament debated the choice of a new Prime Minister, even considering the ally of Chamberlain, Lord Halifax, for the position. After much debate, English House of Commons chose as Chamberlain's successor the former Lord of the Admirality Winston Churchill, a strong militarist with a checkered background. It was clear that Churchill would offer the type of strong military leadership that his predecessor lacked. In his first speech to the Ministers of the Admirality, Churchill gave the famous "blood, sweat, toil, and tears" speech, declaring a vision of England the defender of the Free World:

You ask, what is our policy? It is to wage war, by sea, land and air, with all our might and with all the strengtht that God can give us; to wage war against a monstrous tyranny, never surpassed in the dark, lamentable catalogue of human crime. That is our policy.

After the withdrawal of Allied forces at Dunkirk, Churchill began anticipating an invasion by Germany. He nixed plans that called for the removal of British goods to Canada, demanding instead that total attention be payed to the defense of the United Kingdom. To develop a psychological commitment to defense, Churchill gave his famous "Fight on the Beaches" (excerpt) speech to the House of Commons. It was clear to everyone in England that should an invasion by Germany occur, it would a battle that would be fought with tenacity and courage.

The few engagements between Germany and Britain had, at that point in the spring of 1940, been limited to a defense of France. After the fall of France, Hitler did not know if Churchill would continue to fight, or sue for peace. Hitler's question was answered by the British battle at Mers-el-Kebir.

Mers-el-Kebir was the sight of the French fleet in the province of Algeria. After Dunkirk, and the establishment of a collaborationist government at Vichy under Marshall Petain, it became apparent to Churchill that French ships had become German ships. In the armistice, British negotiators had attempted to keep this force out of the war, but the Germans refused. In response, Churchill ordered an attack on these ships, the ships of his allies of two weeks previous. In the attack, the British Royal Navy destroyed several ships, including the Dunkerque and the Bretagne , and with 1,200 French sailors dead.

The attack was to cause ripples in the French/German negotiations. Some French began to accept that its salvation rest with Nazi collaborationism. For Hitler, the attack meant that an easy settlement with England could not be reached, and an invasion might become necessary. On July 16, 1940, Hitler signed Directive 16, which named the invasion "Operation Seelowe" (Sea Lion), and called for a force of ninety thousand men to land on the English beaches for an invasion.

Hitler worked both sides of the equation, planning an attack while offering peace. On July 19, Hitler proposed an armistice, while both deriding Churchill and threatening an invasion and the eventual decimation of England. The English were naturally not receptive to this proposal. As one BBC commentator, in a commentary directed at Hitler, stated, "Herr Fuhrer, we hurl it right back at you, right in your evil smelling teeth!" There was to be no peace. Plans for Sea Lion began on the tactical level.