Franklin Delano Roosevelt, or FDR, was elected president four times. He led the US through the Great Depression and the second world war – and in the process championed social security, modern labour standards, and his still resonant four freedoms: freedom of speech, freedom of religion, freedom from want, freedom from fear.

Roosevelt was opposed by some of the strongest corporate interests of his time, but he refused to let their opposition dictate the nation's course. He was positive and inspirational, but he did not shy away from the good fight.

Here's FDR addressing a crowd at Madison Square Garden in 1936. Let's hope that when President Barack Obama speaks before the Democratic National Convention on Thursday – one of the biggest speeches of his political life – he remembers that this is the legacy he carries:

FDR was reelected president the month after he gave this speech – with 60% of the popular vote. If you believe the US and the world needs great, inspirational leadership, share this with everyone you know.