"The best friend that the United States ever had," is how House Speaker John Boehner described the statesman who spoke to a joint session of Congress in 1941 just 19 days after the attack on Pearl Harbor and called on America to stand firm in the face of war.
It was one of three addresses to Congress, more than any other foreign dignitary, by Churchill, who held a lifelong love affair with the United States -- his mother was American -- and was made an honorary citizen by president John F Kennedy in 1963.
The premier's powerful oratory, Kerry said, "literally rescued the world."
In 1946 Churchill gave remarks that later became known as his "Iron Curtain" speech at a small college in Fulton, Missouri.
More From This Section
At today's ceremony, Daltrey, lead singer of iconic British rock group The Who, sang their classic "We Won't Get Fooled Again" as well as Ben E King's "Stand By Me," altering the final stanza to reflect the "shoulder-to-shoulder" alliance between Britain and the United States.
Despite the British burning of the US Capitol in 1814, Churchill's grandson Nicholas Soames said the late leader loved the structure.
"He thought this building was a kind of center of the universe, really, apart from his own country," said Soames, a longtime British MP.
As for the latest row between America and Europe, over US surveillance, Soames dismissed it as a petty squabble.
"Everyone spies on everyone else," he said, adding that Churchill would have reacted the same.