Chantal Hebert of the Toronto Star seems to think so, particularly in Quebec, which she says is "hotbed" of anti-missile-defence sentiment. And Quebec holds the key to a Liberal majority government.

An excerpt:

Notwithstanding the recurring headlines about Liberal divisions on same-sex marriage, missile defence is ultimately more likely to stand in the way of Paul Martin's bid to rally his party and go on to win a majority in the next election than the expanded recognition of gay rights.

In the marriage debate, the Prime Minister is at least on solid Liberal ground.

More so than any other federal party, the Liberal party sees itself as the guardian of the Charter of Rights and Freedoms, which it considers its most distinguished contribution to Canadian public life.

The plan to expand the definition of civil marriage is also in sync with the favourable bias to individual rights that has long been a trait of the party's personality.

In contrast to his Conservative counterpart, the average federal Liberal activist tends to see social conservatism as a deviance, rather than a defining part, of his or her party's character.

Indeed, many Liberal insiders, from MPs to grassroots members, see the social conservative Liberals nested within the government caucus at best as an imposition on the normal life of the party and, at worst, as an aberration. Missile defence, on the other hand, finds Martin on shifting Liberal sands.

In many ways, it is to the Liberal leader what same-sex marriage is to Conservative party leader Stephen Harper — an issue that is closer to the heart of a vocal section of his party than it may be to Canadians in general.

In sharp contrast with Liberal foes of same-sex marriage, those within the governing party who oppose missile defence are as mainstream as they come.

For further reading on how social issues are causing problems in both parties, see Hard right playing hardball in Conservative Party.