When Maori tikanga and the rules of Parliament clash; Te Pati Maori's extraordinary display of protest yesterday - interrupting the first vote on the Treaty Principles bill - has highlighted the distance between the two. When called on to cast Te Pati Maori's vote, its MP Hana-Rawhiti Maipi-Clarke instead launched into a haka, ripping a copy of the legislation in half. She was joined by other opposition MPs and onlookers, prompting Speaker Gerry Brownlee to temporarily suspend Parliament and clear out the public gallery. Now, coalition members are calling for decorum, while others say yesterday's scenes are part and parcel of the debate. Political reporter Lillian Hanly reports.