TOKYO — Visits by Cabinet ministers and lawmakers to a shrine honoring Japan’s war dead, including 14 World War II leaders convicted of atrocities, signal Prime Minister Shinzo Abe’s determination to pursue a more nationalist agenda after months of focusing on the economy.

Nearly 170 Japanese lawmakers paid homage at Yasukuni Shrine on Tuesday. A day earlier, visits by three Cabinet ministers, said by the government to be unofficial, drew protests from neighbors South Korea and China over actions they view as failures to acknowledge Japan’s militaristic past.

China and South Korea — Japan’s No. 1 and No. 3 trading partners, respectively — bore the brunt of Tokyo’s pre-1945 militarist expansion in Asia and routinely criticize visits to the shrine. Almost seven decades after the war ended, it still overshadows relations....