Who is more powerful Iago or Roderigo?

Iago holds all the power in this relationship. Roderigo wants Desdemona, desperately. He's kind of like her creepy stalker except if Othello found out; he would turn him into a pretzel. Iago is able to manipulate him to do his bidding by telling Roderigo that he will win Desdemona's hand for him. This of course never happens and after the marriage, Roderigo gets more desperate. Iago convinces Roderigo that Cassio is another potential suitor and must be dealt with before Othello. Roderigo is pretty pathetic and Iago easily uses him to achieve his own evil ends.