Hong Kong Financial Secretary Paul Chan Mo-po recently said the city could rise to become the world’s No 2 financial centre in 10-15 years. That is the right kind of ambition. In a world being reshaped by geopolitical fragmentation, China’s growing global weight and rapid technological change, Hong Kong must think beyond remaining internationally competitive to exercising global leadership.

But ambition alone is not enough. Hong Kong has spent decades proving it can operate at the world’s...