Shinzo Abe, Japan's struggling prime minister, will stick to his guns by keeping constitutional reform at the heart of his party's platform when he fights a crucial upper house election next month.

The manifesto of the ruling Liberal Democratic party, due to be released last night, will pledge to submit a draft constitution to parliament by 2010, party officials said. In particular, the prime minister wants to amend Article 9, which effectively bans Japan from coming to the aid of allies under attack.