There are a couple of ways of looking at this: let the market decide or have some level of government quash the proposed sale. The former might be in the interests of current shareholders - if there is a good offer, these shareholders could stand to make a substantial profit selling their shares to BHP. The latter really goes against both Federal and Provincial Governments' supposed free market philosophy, but could be justified by declaring this industry a strategic resource - too important to allow it to be sold.
In a somewhat surprising, but understandable, move, the Sask Government has come out against the sale, declaring it not to be in the interests of Canada or Saskatchewan. Given who else has come out against this proposed sale, the Feds will probably come out against it as well.
This is as it should be. There is no perceived benefit to the Province or the country by this sale. This is simply the quickest way BHP can enter the potash business. There have been far too many examples in Canada of valuable companies, good companies, being taken over and run into the ground, broken up or controlled by outside interests. Some industries are too important to allow the "free market" to do whatever the profit motive dictates. Not everything is about money!