In addition to the United States, Japan and Nazi Germany had programs to develop nuclear bombs. And America's program, which included Canada, was founded on the United Kingdom's prior work (just like radar). But the UK, Japan, and Germany ail suffered from limited scientific talent, loss of facilities to military action and over all limited resources. The Soviet program, which did not begin until after World War Two, was substantially aided by information stolen from the American program.
—David Foss