on both sides of the ideological divide. Some will join other groups that are not mainstream.

Most will not do those things. Well over 90% won't join anything that's too far out of the mainstream simply because they've already done their out of the mainstream thing.

The number who will join is directly proportional to the total number of veterans -- thus a draft might influence it but lowered entry standards will have little to no effect; in fact, those who tend to join fringe outfits are the sharper folks. The occasional dummy will get sucked in as a gofer but that's rare -- it's the guy or gal who believe they're smart who fall for it and join.