Radiate and Blatant Thievery

[Puschkin]

Okay, so I play Radiate

Choose target instant or sorcery spell that targets only a single permanent or player. For each other permanent or player that spell could target, put a copy of the spell onto the stack. Each copy targets a different one of those permanents and players.

on a Blatant Thievery

For each opponent, gain control of target permanent that player controls.

So ... what happens?
First off, can I even use Radiate on Thievery in multiplayer? Can I use it if there is only one opponent?

Okay, and if the anwser to either question is "yes", how many permanents do I get? Still just one, two or all permanents the opponent(s) got?

[Gabethebabe]

it´s clear what happens: you get all your opponents permanents, except those that are/become illegal targets upon resolution.

You can´t cast Radiate on Blatant Thievery in MP, because the spell will have multiple targets.

[Puschkin]

Is that really that clear?
I don't target the players! This "for each opponent" is the part that confuses me ... somehow the number of permanents that can be targetted isn't clear at the moment I declare the spell. What if there are 2 opponents but one has no permanents or all of his permanents are not targetable, am I allowed to radiate it?

[Gabethebabe]

Is that really that clear?
I don't target the players! This "for each opponent" is the part that confuses me ... somehow the number of permanents that can be targetted isn't clear at the moment I declare the spell. What if there are 2 opponents but one has no permanents or all of his permanents are not targetable, am I allowed to radiate it?

It says target permanent, so when you play the spell, you have to declare it target(s).
If there are more than two players, your spell will have multiple targets (unless, as you well state, only one opponent has legal targets for Blatant Thievery).

[parallax]

By the time you cast Radiate, you will already have chosen targets for Blatant Thievery. For each opponent, you must choose one permanent that opponent controls. Then, if Thievery has exactly one target, you may Radiate it. This is unlikely to happen in multiplayer. In a duel, however, you can take all permanents that can be targeted by Blatant Thievery.