OTTAWA — The federal Liberals are taking a Conservative MP to task for an Internet article that argues same-sex marriage is not a rights issue, and refers to the prime minister as a hairy knuckled Paul Martin Luther King.

The article, on Alberta MP Monte Solberg's website, criticizes Martin for defending gay marriage as a right under the Charter of Rights and Freedoms.

If Martin defends same-sex weddings as a Charter right, then an argument can be made that reopening the Canada-U.S. border to Canadian cattle is also a Charter right for farmers, Solberg suggested, tongue-in-cheek, in the note posted Sunday.

"Remember, it's all in the Charter and if you don't think so, then you can just take your hairy knuckles back to Selma, Alabama, where you obviously belong,'' he wrote.

The Conservatives have been playing games with the same-sex issue for some time, said Martin aide Scott Reid, adding that he found the references to Martin Luther King in the article "astonishing.''

"I think it's a paid advertisement for the extremism of the Conservative party,'' Reid said.

"I think a lot of people regard Rev. King as a hero.

"They also regard the Charter as fundamental to our rights and freedoms, and they'll find these comments difficult to square with a party that wants to present itself as centrist and moderate.''

Solberg defended the article, saying he wrote it because Martin cloaked himself "in the language of the (U.S.) civil rights movement'' in defending same-sex marriage during the Liberal policy convention over the weekend.

In fact, the reference to Martin Luther King was a favourable one, Solberg argued.

"I'm saying if the prime minister doesn't defend my position (on Charter rights), then he's a knuckle-dragger segregationist just like the ones who attacked Martin Luther King and the civil rights movement,'' Solberg said.

He said the reference was "obviously tongue-in-cheek, and this is satire, which is open to misunderstanding.''

Satire aside, same-sex marriage is not a rights issue, Solberg maintained.

"Marriage is a social institution that, over a period of time, became one that is so important that at one point government came to recognize it officially,'' he said.

"(Governments) saw the value and great social benefits of marriage. But it's not a Charter right, no.''

The Liberals counter that Conservatives, under leader Stephen Harper, argue the point because they don't understand the Charter.

The debate has sharpened since the Liberal government introduced legislation that would redefine marriage to include homosexual couples, in response to several court rulings that barring such unions violates the Charter.

"If there's anyone that is unclear about how the Charter works, what it represents, and what it means to Canadians, it's Mr. Solberg and the Conservatives,'' Reid said.