A summary of the WWII events of this day:

• The German Army in Belgium captured Antwerp and entered Brussels.
• The British and French forces in Belgium fall back to positions behind the Dendre River.
• Twelve RAF Blenheim bombers attacked advancing German columns near Gembloux, Belgium. Eleven of the planes were shot down.
• U.S. President Roosevelt announced plans for the recommissioning of 35 more “flush deck” destroyers to meet the requirements of fleet expansion and the Neutrality Patrol.
• Charles Lindbergh–aviator hero and spokesman for America First Committee–accuses President Roosevelt of creating “a defense hysteria” and states, “If we desire peace, we have only to stop asking for war.”

Winston Churchill wrote the following to Roosevelt:

I do not need to tell you about the gravity of what has happened. We are determined to preserve to the very end whatever the result of the great battle raging in France may be. We must expect in any case to be attacked here on the Dutch model before very long and we hope to give a good account of ourselves. But if American assistance is to play any part it must be available.

From Walter Lord’s book, The Miracle of Dunkirk, BEF Commander Gort’s increasingly disillusioned perspective on his French allies:

… the communications breakdown was one more item in a growing catalogue of complaints against the French. Gamelin was a forlorn cipher. General Georges seemed in a daze. General Billotte, commanding the French First Army Group, was meant to coordinate but didn’t. Gort had received no written instructions from him since the campaign began.

The French troops along the coast and to the south seemed totally demoralized. Their horse-drawn artillery and transport cluttered the roads, causing huge traffic jams and angry exchanges. More than one confrontation was settled at pistol-point. Perhaps because he had gone along with the French so loyally for so long, Gort was now doubly disillusioned.

It’s hard to say when the idea of evacuation dawned on him, but the moment may well have come around midnight, May 18. This was when General Billotte finally paid his first visit to Gort’s Command Post, currently in Wahagnies, a small French town south of Lille. Normally a big, bluff, hearty man, Billotte seemed weary and deflated as he unfolded a map showing the latest French estimate of the situation. Nine panzer divisions had been identified sweeping west toward Amiens and Abbeville—with no French units blocking their way.

Billotte talked about taking countermeasures, but it was easy to see that his heart was not in it, and he left his hosts convinced that French resistance was collapsing. Since the enemy now blocked any retreat to the west or south, it appeared that the only alternative was to head north for the English Channel.