Legal Commentary

An interesting story is developing in the United Kingdom, regarding the "Human Fertilisation and Embryology Bill" now under consideration in Parliament.  (Read more here.)  Apparently, part of the drama concerns the question whether Catholic MPs (and others who object to the Bill on moral grounds) will be given a "free vote" by the Labour Party: 

Cardinal Cormac Murphy-O'Connor, leader of the Roman-Catholic Church in England and Wales, yesterday became the most senior clergyman to insist that Labour MPs should be granted a free vote.

He urged Catholic MPs - including Cabinet ministers Ruth Kelly, Des Browne and Paul Murphy - and those of other faiths to be guided by their religious convictions.

So far, Labour has refused to follow Parliamentary tradition on issues of conscience and allow MPs to vote as they wish on the Human Fertilisation and Embryology Bill, though it has in the past given free votes on issues such as hunting, reform of the House of Lords and fluoride in drinking water.

Instead, MPs will be whipped - meaning they could face disciplinary action if they refuse to support the Bill. . . .

What's the current thinking among political scientists on strong whip policies, party discipline, etc.?  Putting aside our views of the merits of the proposed Bill, is it better (and, if so, by what measure?) if a Party can effectively require legislators to vote with their Party on things the Party's leadership really cares about?