First off, Roosevelt didn't die because he had polio, but having been struck by that terrible disease was a major life changer. I seriously doubt we would be talking about the same historical figure if FDR hadn't been afflicted.
He died from a stroke. It also should be noted that there was a family history of cardiovascular problems.
But all right, assume his health is a bit more robust and he lives as long as his father, another 9 years.
Start with his own words, from his 1944 State of the Union address:
"In our day these economic truths have become accepted as self-evident. We have accepted, so to speak, a second Bill of Rights under which a new basis of security and prosperity can be established for all — regardless of station, race, or creed.
Among these are:
The right to a useful and remunerative job in the industries, or shops or farms or mines of the Nation;
The right to earn enough to provide adequate food and clothing and recreation;
The right of every farmer to raise and sell his products at a return which will give him and his family a decent living;
The right of every businessman, large and small, to trade in an atmosphere of freedom from unfair competition and domination by monopolies at home or abroad;
The right of every family to a decent home;
The right to adequate medical care and the opportunity to achieve and enjoy good health;
The right to adequate protection from the economic fears of old age, sickness, accident, and unemployment;
The right to a good education.
All of these rights spell security. And after this war is won we must be prepared to move forward, in the implementation of these rights, to new goals of human happiness and well-being."
