The Westminster system is distinguished by a particular entwining of powers, such as in New Zealand and Canada. Canada makes limited use of separation of powers in practice, although in theory it distinguishes between branches of government. New Zealand's constitution is based on the principle of separation of powers through a series of constitutional safeguards, many of which are tacit. The Executive's ability to carry out decisions often depends on the Legislature, which is elected under the mixed member proportional system. This means the government is rarely a single party but a coalition of parties. The Judiciary is also free of government interference. If a series of judicial decisions result in an interpretation of the law which the Executive considers does not reflect the intention of the policy, the Executive can initiate changes to the legislation in question through the Legislature. The Executive cannot direct or request a judicial officer to revise or reconsider a decision; decisions are final. Should there be a dispute between the Executive and Judiciary, the Executive has no authority to direct the Judiciary, or its individual members and vice versa.