Marine Services International Ltd. v. Ryan Estate, 2013 SCC 44 effectively eliminates the doctrine of interjurisdictional immunity:
Interjurisdictional immunity exists to protect the "basic, minimum and unassailable content" or the core of the "exclusive classes of subject" created by ss. 91 and 92 of theConstitution Act, 1867: Bell Canada, at p. 839. This Court discussed interjurisdictional immunity in Canadian Western Bank and later in Quebec (Attorney General) v. Canadian Owners and Pilots Association, 2010 SCC 39,  2 S.C.R. 536 ("COPA"). The doctrine has a limited application today: Canadian Western Bank, at paras. 33-34. InGeneral Motors of Canada Ltd. v. City National Leasing,  1 S.C.R. 641, Dickson C.J. stated that the dominant tide of constitutional interpretation, which favours, where possible, the operation of statutes enacted by both levels of government, militates against interjurisdictional immunity. A broad application of the doctrine is inconsistent with a flexible and pragmatic approach to federalism. As stated earlier, interjurisdictional immunity "is of limited application and should in general be reserved for situations already covered by precedent": Canadian Western Bank, at para. 77.