n. — Politics
a provision automatically terminating a government programme or law at the end of a fixed period unless they are formally renewed.
The history of sunset clauses goes back to 1789 when Thomas Jefferson argued that ''no society can make a perpetual constitution, or even a perpetual law'' (Ranchordás 2014: 18). Jefferson believed that laws should terminate after a fixed period since one generation has no right to inflict their decisions upon younger ones. Even though Thomas Jefferson wrote about 'sunsetting', the actual term sunset clause, also known as sunset law (see 1977 reference) was popularized by Colorado Common Cause founder Craig Barnes. The term was used as a 'companion concept' to sunshine law (see AHD-5) to describe a process where, unless agency and purposefulness is proven, the 'sun would set' on the regulation.
The basic concept is therefore, clearly, not Canadian. However, internet domain search raises further questions, since the hits are highest for South Africa, then Australia. Surprisingly, both Canadian and American figures are very low (see Chart 1) in the international context.
In the light of this evidence a Canadian dimension remains when defining the meaning narrowly in the political context, as in .za domains the less political construction context is prevalent.
- 1977  [He called for a "sunset law" in which every facet of a Ministry is examined every five years for redundancy, and if found to be redundant is cut out.] 
- 1978  The northern pipeline agency legislation includes a "sunset" clause requiring the disbanding of the agency a year after the pipeline has begun operating. However, the legislation does give Parliament the option to continue or reconstitute the agency if a lateral connection to the Mackenzie delta is approved using the Dempster Highway route. 
- 1988  The three funds were set up to invest in Government of Canada bonds and to seek extra earnings by dealing in options on bonds.They are closed-end investment trusts with fixed numbers of shares.The first two funds, Canada Income Plus Fund and Canada Income Plus Fund 1986, have a "sunset" clause requiring them to be wound up at the end of the century with the proceeds distributed to unit holders. 
- 2000  Peter Clarke explained how the misconception came about:
"As we went down the road with RMH, the project didn't come together as quickly as we first thought and people forget TJF had a sunset clause. You can't expend funds after the end of a program."
- 2010  "Basically what it does is frees up cash flow up front and allows them to build. The whole purpose is to attract business to the area and create jobs. We want to encourage them to build as soon as possible to stimulate the economy. There is a sunset clause on it, they have until March 31, 2011 to apply for the program and the completion of their project by 2013. These things will disappear if businesses don't use them," said Arsenault.
- 2015  Mr. Trudeau said his priority will be to "address the gaps" in the bill. In particular, the Liberals will push for parliamentary oversight of Canada's national security agencies, and try to add a sunset clause that would force Parliament to evaluate the legislation before it is periodically reenacted. 
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Chart 1: Internet Domain Search, 22 April 2015