Did President Roosevelt consider American public opinion when deciding how to respond to the conflict in Europe?
FDR had to take public opinion into account, because the majority of Americans wanted nothing to do with another war in Europe. At the same time William Stephensen, a Canadian businessman and head of British Security Coordination acted as a go-between for communications between Churchill (not yet Prime Minister of Britain) and Roosevelt. These three and William Donovan (who later headed the Office of Strategic Services) covertly set up offices in New York and training areas in Canada to keep an eye on Nazi agents and prepare for eventual war. This began well before the war actually started in Europe.
The intelligence cooperation between these men and others (such as J. Edgar Hoover and intelligence agencies in other countries) laid the groundwork for the succes of the secret armies built up in Europe from the late 1930s on. German business conglomerates had deals with hundreds of corporations around the world and owned dozens of subsidiaries globally, all of which were used by German intelligence. The business contacts of Stephensen and the others enabled BSC to use companies such as International Telephone and Telegraph as intelligence agencies, also. This cooperation enabled the Western powers to collect contacts, agents and all that was necessary to build up resistance operations in Europe once war began.
The problem for FDR was that all this had to be done secretly, or public opinion would turn against the Allies, or against FDR and a new president less concerned with the looming world war take office. He had to gradually change opinion in America, and mollify many political opponents of his plans. The FBI also had to be given credit for successes against espionage networks in America, so the public would not become aware of the British intelligence agency on American soil. As the war went on the behavior of the Nazi diplomatic corps and occupation troops began to turn public opinion toward a grudging acknowledgement that our country would probably be drawn in.
One casualty was the early civil rights movement, championed by Eleanor Roosevelt. FDR was forced to shy away from any federal pressure on states with discriminatory laws, lest he lose political support necessary to remain in office and continue the secret war.
One of F.D.R.'s best political qualities was his ability to assess a situation, understand it for what it was worth, and depending upon what it was worth find a solution. Yes, F.D.R. considered American public opinion because he had to. Isolationism was a post W.W.I. reality and he knew it. During the 1930's Congress passed several Neutrality Acts turning the policy of isolationism into law. As president Roosevelt was not about to break the law, however he would test the waters. The Quarantine Speech he delievered in 1937 argued that nations promoting aggression should be denied trade relations. The speech was met with a luke warm response and as a result Roosevelt deferred. Between 1938-39 it was self evident that the Munich Conference was a joke, Hitler was on a rampage. The invasion of Britain led to the 'Lend-Lease Act' which allowed the U.S. to legally avoid the trappings of the Neutrality Acts. By 1940 many Americans believed Hitler's assault might end up on America's shores, isolationism began to faulter. The final act to sway American public opinion...12-7-1941...the attack on Pearl Harbor. On 12-8-1941 Roosevelt went to Congress and asked for a declaration of war with the blessing of American public opinion.
Absolutely he did. Roosevelt wasn't elected four separate times for no reason. He was a fantastic politician who knew that the American people were mired in the Great Depression, and in no mood to become involved in what they viewed as "Europe's War". This is a sentiment known as isolationism.
While FDR was well aware it was not politically possible for the US to enter the war, he also knew that he had to do something to help out the Allies, who were losing badly in 1939-40. So take Cash and Carry policy as an example of his bending to the isolationism of the time - all weapons sold to Britain had to be paid for in cash, and carried on British ships, so it would not appear to either Germany or war-reluctant Americans that we were entering the fight.