CRA has recently posted two new web pages on Charities and political activities (Budget 2012) and The audit process for charities.  

The two pages have some new information and statistics but really are just cogent expressions of the CRA's views.   

In the Charities and political activities (Budget 2012) it notes:

“Importantly, these 60 audits include a charity’s political activities but also examine whether or not the charity is following all the rules for charities and is operating for charitable purposes. Some have already been completed and reveal a range of non-compliance problems related to both political activities and other rules for charities issues. The CRA will continue to use its education-first approach to help charities better understand all of the requirements for registration.”

Charities should be aware of the rules for being a registered charity and comply with those rules.   While most political activities are not even that contentious and don't result in much scrutiny from stakeholders, even if you are going to be involved with highly controversial or “toxic” types of political activities or positions then it is probably a good idea to do a risk assessment on your regular compliance with the Income Tax Act and make improvements and changes to your systems before engaging in such activities.  CRA finishes with an awkward statement “Any organization is free to decide not to register as a charity if it wants to pursue political activities that go beyond the limits required by the law.”  Another way of putting that is don't become a registered charity if you don't want to comply with the rules.  Or as CRA suggests in CPS-022 you can also have a non-profit that is not a charity, in addition to the charity, and it has almost unlimited flexibility in terms of political activities.