Alcibiades could not be trusted, for he didn't care about any form of government he only wanted a change in the Athenian constitution so he could then get his partisans in Athens to demand he be allowed to return.
He only wanted a change in the Athenian constitution. This was what alcibiades could not be trusted. He didn't care about any form of government. He could then get his partisans in Athens. This was to demand he be allowed to return. Phrynichus' main argument was this.