Maxime Bernier is seen at the Conservative leadership candidates' bilingual debate in Moncton, N.B. on Tuesday, Dec. 6, 2016. Conservatives vote for a new party leader on May 27, 2017. THE CANADIAN PRESS/Andrew Vaughan

Immigration has become a very contentious issue in politics. We've seen in recent years the rise of anti-immigration parties in Europe. It featured prominently in the U.S. presidential election. And it has become part of the debate in the Conservative Party of Canada leadership race.

Canada has always been a country largely open to immigration, because of its vastness and its relative youth. I believe that by and large, our immigration policy has been very successful. But we are not immune to the conflicts and social tensions happening elsewhere.

We can avoid these tensions if we stay away from ideological extremes and go back to a fundamental principle: The overarching objective of Canada's immigration policy should be to fulfill the economic needs of our country.

In particular, it should answer the needs of sectors where there is a scarcity of manpower with specialized skills; and in more general terms contribute to increasing the number of younger workers in a society that is fast aging.

Too little immigration means we will not get as much of these economic benefits as we could. But too much immigration also has its dangers.

Our immigration policy should not aim to forcibly change the cultural character and social fabric of Canada, as radical proponents of multiculturalism want. The vast majority of Canadians rightly expect immigrants to learn about our history and culture, master one of our official languages, and adopt widely shared Canadian values such as equality of men and woman, tolerance for diversity and respect for Canadian law.

At too high a level, immigration ceases to be a tool to economically benefit Canadians, and it turns instead into a burden.

Immigrants are expected to integrate in our society, not to live in isolation and try to replicate the way of life of their country of origin in Canada.

Of course, Canadian society is also transformed by immigration, as it has for centuries. But this has to be done organically and gradually. When it happens too fast, it creates social tensions and conflicts, and provokes a political backlash, as we can see today in several countries.

This is why I am opposed to increasing the annual intake of immigrants from 250,000 to 300,000, as the Liberal government has announced.

I am even more opposed to the proposal made by the government's advisory council a few months ago to increase it to 450,000, which Liberal Immigration Minister John McCallum said could be adopted at some point in the future.