It is an inevitability. Just like with the Lib Dems/Labor in the UK.
I honestly thought that was meant sarcastically until I read the remainder.
The Liberals will find survival in the center hard if they are relegated to third place in the longish run. Yeah, I know it worked out in the end - somehow - for the British Liberals, but it's not something you can count on. Small wonder, then, that Liberal apparatchiks think about it - sane self-defense strategizing.
And Chretien, of course, would probably not be so averse to the policies of a putative merged party.