Theoretically, giving women the vote creates an immediate majority. 51% of the population is female, 49% is male. Now, that's not quite enough to rig the political game, since you can't expect 100% of women to vote left, so here comes intersectional feminism and muh diversity to lock it in. The feminists claim all racial minorities and sexual minorities of both sexes for themselves. A quick google tells me that's 71.8%. Again, not all minorities and gheys can be expected to vote left, but that probably makes the split 65/35.

e: Also, women are generally going to be amenable to the idea of voting for free shit they didn't work for, for obvious reasons....