the shift would need to be more to the right but not passing centre. a liberal-ndp party just slightly left of centre. it wouldn't strengthen the green party. the green party is slightly right of centre. they can join the liberal-ndp club too.Hmmm... If the Liberals merged with the NDP and shifted further to the left, the Convservatives could just get their federal majority.
The only way I could really see merger helping is if the NDP shifted to the right to become very Liberal-like, but my guess is that all that would do is strengthen the Green party.
the worst thing to happen was the merger of the CRAParties. when there's 1 rightwing choice and many left wing choices, the rightwing will always prevail. in the next toronto mayoral election, the left needs to get unified behind one good candidate. fragmentation is a bitch.