If an opponent declares an attack on a character I control with the Villains United affiliation, and I play Join Us or Die before the attack is declared legal, will the attack still continue/be legal after my character recovers from the effects of Join Us or Die, or will the attack declaration have become illegal when the proposed defender became stunned?

yes, i think the attack will push thru since it's the same target and the attack is still legal.

i could be wrong though, hehehe.

Legality only matters when you initially propose, and when the attack substep starts. As long as the character is unstunned and still attackable(isn't protected or hidden or something), and is still the same object(hasn't left play or anything), when the attack substep starts, the attack will be declared legal.

Remember your timing:

Declare potential attacker and defender
Opportunity for effects / Pass on priority
Characters become "attacker" and "defender" and the attackers exhaust.

So with JUOR, you can stun/recover your VU character during the priority step, and then still have the characters resolve and become attackers/defenders.

Thanks HomerJ. Just making sure, since the 601 Rules are kind of hard to understand.

In terms of 601, it has to list all the legality issues because the proposing player needs to make a legal proposal in the first place. But once he has made a proposal and passed the first check, the second check doesn't happen until 602, which as everyone said, is when the attack is actually starting.

Even though it's not an issue of targets, it's very similar to how target legality is checked only twice---once as it's chosen, again at resolution. Legality isn't checked in between, so if the opponent makes a target illegal, you still have a chance to make it legal before the check.

SO MUCH MORE SENSE! Thank you both HomerJ and HeroComplex for laying it all out like that.

...darn, that means I should have lost to JackimusPrime's Outsiders/Villains deck...