“The war in Europe had not yet started’’.<< The Germans invaded Poland on Sept.1, 1939. They invaded Norway on April 10, 1940 and a month later they attacked Holland and then France. They attacked the Soviet on June 21,1941.
The earlier writer was trying to point out that the British beaches were no longer threatened by German invasion, that there were no invasions into Europe/Africa planned (or even possible BY the Allied forces), and the fighting in Russia was heading the other direction. Roosevelt had NO reason to focus on Germany - or even aid to Britain! - until the troops in the Philippines were supported.
Except the pressure from Russian communists in Britain and inside the US government to support Stalin’s murderers against Hitler’s murderers.
After May 1942, the situation was different. But our first invasion into Guadalcanal was even after that.
Our involvement did not start until after 12/7/41. If Hitler had not declared war on the USA, he would only have a 1 front war and would have developed the A-bomb first.
In all likelihood, he would have won the war.