Liberal Leader Justin Trudeau tried to clarify his abortion policy over the long weekend, saying he knows people were "troubled" by it.

New MPs in his party, he said, can be personally opposed to abortion as long as they vote along party lines on any bill or motion that tries to restrict a woman's right to choose.

It was an attempt to straighten out the impression Trudeau made in an announcement on May 7 when it seemed to some that would-be candidates might be scrubbed on the basis of their personal views.

In the foyer of the House of Commons, Trudeau told reporters that candidates for Liberal nominations would be screened about how they "feel" about issues such as same-sex marriage and abortion.

On Monday, Trudeau released a message on the Liberal.ca website.

Trudeau spelled out that "Liberal MPs are welcome and encouraged to hold fast to their personal beliefs."

But he asserted, "Under my leadership, incoming Liberal MPs will always vote in favour of a woman's fundamental rights."

Party must speak with 'one voice'

Trudeau continued, "When it comes to actively supporting women's rights, our party must speak with one voice."

The use of words such as "must" and "will always" seemed to leave little doubt that if new MPs don't vote the party line on abortion, they could face unpleasant consequences such as being cut out of critics' roles, positions on committees or MPs' travel.

A whipped vote can even result in a miscreant MP being kicked out of caucus. In the past, the Liberal Party allowed free votes on so-called issues of conscience.

Rob Oliphant, a former Liberal MP and an ordained United Church minister who is seeking the Liberal nomination for the Toronto riding of Don Valley West, said at first it wasn't clear to him that a candidate who has an "alternative" view on abortion could run.

In a phone interview he explained he had no trouble telling the Liberal Party's screening or "green light' committee he supported a woman's right to choose.

Concerned candidates wouldn't be 'green-lit'

But, he added, "I did have a concern that people who hold another value or different religious view or whatever would be stopped from running, would not be green-lit. That is a bother to me, because we're a big tent party."

Oliphant said he was reassured by reading that Liberal MP Wayne Easter told a Charlottetown newspaper a person who has anti-abortion views could become a Liberal MP, but he or she would be expected to vote along party lines.

Oliphant assumed, he said, adding "these are my words," that "they would suffer the consequences as anyone would when they break a whipped vote."

That, said Oliphant, is "advance notice to a person so they can self-select and say, 'If I can't live with that then I won't run.'"

Easter, reached by phone in P.E.I., described himself as the only MP on the Island who "ever was pro-choice." Easter said he didn't know if a vote on abortion would be whipped, and noted that Trudeau was asked the same question by a reporter during his May 7 announcement .

"That's a tough one," Trudeau replied, and then, as Easter put it, "He moved away from it."

'Maybe you don't vote'

"Maybe you don't vote," Easter said. "I've seen people not vote because morally they couldn't support a position, or a belief system, or whatever."

He continued, "That's one of the possibilities. The only person who can answer whether it will be a whipped vote is the leader."

Trudeau's office did not reply to an email from CBC News about whether votes on abortion would be whipped.

Sean Casey is a P.E.I. Liberal MP who has strong anti-abortion views. On May 9 he issued a statement saying, "I have openly expressed my personal struggle with this issue in the past."

However, he continued, "My personal views should not come first." He then went on to clarify Trudeau's stance, which he said the public had misunderstood.

"Candidates who hold a pro-life view won’t be barred from running. Their personal views will remain their own," Casey wrote.

But, he added, "It’s expected that they will commit to upholding the position of the Supreme Court, regardless of how difficult this may be for them."

Other parties on abortion

NDP Leader Tom Mulcair has said no current or future NDP MP "will ever vote against a woman's right to choose."

The Conservatives allow a free vote on abortion issues.

Green Party Leader Elizabeth May, reached Tuesday in her B.C. riding of Saanich-Gulf Islands, said the Green Party "around the world" never whips votes and she doesn't, under her party's rules, have the power to unilaterally reject a nomination candidate who holds anti-abortion views.

She said, however, that the Green Party "supports unequivocally a woman's right to access safe legal abortions."

May, who once studied to become an Anglican minister, added, "My own personal views are that, as a practising Christian, part of my understanding of protecting life is that we must have access to safe and legal abortions. Otherwise women die."