"A clever riposte to those who want to ban MPs from switching parties is to bring up the question of free votes. Isn't an MP who votes against the party line just like one who crosses the floor? Shouldn't that be forbidden, too, in the name of holding MPs accountable to the voters who elected them?"
I will let it simmer and respond to this in good time. I gotta give it to Andrew; he is well thought out, principled, and not afraid of any opposing strong arguments. I like that. More later.
In the meantime, read the questions that I posed earlier that are somewhat 'answered' by Coyne in his post, most notably number 2 and 3:
1) :: Should we hold a by-election every time an MP falls behind, in popular support, to another candidate?
2) :: Should we hold a by-election every time an MP votes against his party?
3) :: Should we hold a by-election every time an MP acts with his own judgment rather than what a survey indicates constituents want?