A top candidate for Japan''s next prime minister says Taiwan is the front line of democracy, and that Japan must build up its capabilities to counter Chinese aggression.

Speaking to the Wall Street Journal, former Japanese foreign minister Kishida Fumio said his country should hold simulations with the U.S., to prepare a response to a Chinese invasion of Taiwan. Kishida is one of two top frontrunners in Japan''s leadership race, which will be decided in a party election on Sept. 29. Shortly after that, Japan will hold its general election for its House of Representatives. Taiwan scholars say that for these two elections, Taiwan will prove to be a key campaign issue.