Invariably, one of the main challenges facing us when we attempt to create a mass organization based on the principles of class struggle, whether it be a coalition, or a party, is how to achieve sufficient mass. Regardless of the politics of such an organization, if it does not achieve sufficient mass, it becomes just another small, far left group that provides in-services for the left.

To use an example, the IS has, for a while now, devoted most of its energies to the war resisters campaign. I would argue that much of this effort has been wasted. However, it has been wasted not because asylum for war resisters is in any way an undesirable or irrelevant goal (quite the opposite, it is an important cause, and would be a desirable victory). Rather, much of  the effort has been wasted because there have not been large enough mass mobilisations on this issue to actually force the Conservatives to implement the parliamentary resolution calling on the government to grant asylum for US war resisters.

To take a recent example, the CPC supported the NDP-Liberal coalition (they have supported a coalition with the Liberals since 1935, when Stalin mandated that all official Communist parties adopt a "common front" policy). The IS opposed the coalition, their primary stated reason being that they opposed the NDP dropping any opposition to the Afghanistan war. Big Difference.

Another substantive difference is that the CPC supports the FARC in Columbia, while the IS does not. As far as I know, the CPC is the only Communist/Marxist group in Canada that supports the FARC.