That's a good point. On the one hand, you have entryism; on the other hand, you have cooptation -- the environmental movement, for example, has been coopted by the Democrats here in the US, and the anti-abortion movement by the Republicans; neither party does anything for the groups they've coopted, because they can simply wave the other party around as a bogeyperson come election time and get the coopted groups to line up meekly and vote for another candidate who won't do a thing for the causes they favor.