Ever since Berkshire Hathaway Energy announced it would buy up Calgary-based AltaLink Ltd (an electricity transmission company with 12,000 kilometres of power lines), the predictable protectionist sentiment ramped up.

The deal is worth $3.2 billion for AltaLink’s current owner, Montreal-based SNC-Lavalin; some urge the federal government to quash the proposed sale. Opponents assert the AltaLink takeover by a Warren Buffett-run company should be blocked because:  Electricity lines are “critical infrastructure”—a “lifeline” according to Joe Anglin, Wildrose environment, water and utilities critic; an American company would “reap the benefits” according to NDP leader Brian Mason; some Albertans are apparently paranoid about electricity exports; Buffett and his company are presumably motivated by profit and/or are only loyal to the United States.

None of the justifications withstand a cursory analysis. The paranoid protectionists will always be obsessed about exports be they oil, lumber, electricity or water. If governments listened to them we’d be back in the Great Depression when many countries imposed barriers to trade and investment and exported little except comparisons on which country was the most poor.

That a company has headquarters in Montreal, Omaha or Calgary is largely irrelevant. Shareholders of such companies only make a buck by catering first to consumers and not, in this case, by turning the lights off.

As for the “critical” nature of transmission lines, they are not alone: forestry. Agriculture, oil and gas, railways, automotive and aerospace companies and their products are also critical—to feed Canadians, keep us from freezing in winter, or to fight a war (automotive assembly plants can be converted to produce tanks).

Such critical elements of an economy though are hardly an argument to block foreign investment from Americans, Australians and other allies historically friendly to Canada. Do opponents of the AltaLink deal fear the 83-year-old Warren Buffett and his 90-year old partner Charlie Munger will one day invade Canada, from Omaha?

There are occasions where foreign ownership restrictions are necessary; for example, preventing the Iranian and North Korean governments from buying up uranium.

Beyond that, the anti-foreigner, anti-foreign investment tack is counter-productive. Canada was built on foreign investment. That includes the fur trade four centuries ago and the oil patch and automotive sectors in the last century and newer industries now.

Besides, according to Statistics Canada, foreign money already has a significant presence in Canada: In mining ($20.8 billion); finance and insurance ($94.5 billion); management of companies and enterprises ($116.2 billion); oil and gas extraction ($107.2 billion); or the mother of all foreign investments: manufacturing ($209.3 billion).

But when some Canadians get touchy about foreign investment, they forget that what they recommend for the foreign goose could cook the Canadian gander. Plenty of Canadian cash is invested outside of Canada (and which comes from mutual funds, Canada Pension Plan money, union retirement plans, and other Canadian investors).

Outside of Canada, Canadians have investments in oil and gas extraction ($49.8 billion); mining ($66.3 billion); manufacturing ($72.7 billion); management of companies and enterprises ($101.5 billion) and finance and insurance ($312.9 billion).

In total, Canadians have more investment outside of Canada ($779 billion) than do foreigners here ($686 billion). That, by the way, includes the utility sector where in 2013, foreign money in Canadian utilities was worth $5.7 billion. That was a trifle compared to the $18.8 billion of Canadian cash invested abroad in other countries’ utilities.

This is a critical point. Canadians are net exporters of capital, profit from it, and always lose when global trade and investment barriers rise instead of fall.

Foreign investment—whether in Canada by “foreigners” or by Canadians elsewhere—provides new capital that domestic investors either don’t have or won’t provide. Moreover, investor money bulks up existing industries or creates new ones. And investors often bring new expertise to the country in which they operate. (As an example, Canadian bankers could teach Europe and America about not overdoing it on risk). Finally, investment creates jobs.

Existing shareholders also profit from outside investors who obviously see a higher value where domestic firms do not. That also explains why some domestic companies complain about foreign investors. Without money from abroad, Canadian-based companies (albeit also ones with shareholders from the world over, it should be remembered) could pick up companies on the cheap—to the detriment of existing shareholders.

Foreign investment is a win-win-win-win proposition for countries, consumers, the economy and shareholders. The only losers? Companies who dislike competition—or people who think Warren Buffett poses an existential threat to Alberta.