Vaughn creeps up on Lucas to demand classified intelligence files. From the first moment, it was clear that Lucas should have tossed Vaughn off a bridge. Once he got played by Vaughn, the stories got dumber and dumber. On the one hand, Lucas is ruthless in dealing with Harry, but on the other hand he is easily manipulated by Vaughn.
The love affair with Maya who has not seen Lucas / John for 15 years and immediately jumps into bed with him is weak and pathetic. In the space of days they are planning to marry and move to another country. The fact that Maya is a doctor with a medical practice and professional work contracts is totally ignored.
The worst writing is saved for Harry, who acts like a lovestruck schoolgirl when it comes to trusting Lucas / John. Even after Lucas totally explains that not only did he blow up the British Embassy in Dacchau, but he also killed the real Lucas to get his identity and his MI-5 job, Harry gives Lucas his gun and lets him go. Even a brain-dead amoeba could have guessed that Lucas was going to continue after the Albany file, and he did. Ruth was the logical target, and Harry chose trusting Lucas over the safety of Ruth. Just incredibly lame and pathetic on the part of Harry.
Thanks to Harry, several people were murdered, and Harry commits treason in order to save Ruth. If Harry had not released Lucas, Ruth would never have been in danger. I honestly hoped that Lucas was going to blow Harry's head off at the end, or that Ruth would. Ruth was the first one that warned Harry about Lucas, and Harry refused to listen to reason and the evidence. Harry's bromance with Lucas / John was more important to him than his job, and Ruth.
Overall, Harry was a bigger disappointment than Lucas, but both of them became major traitors and disappointments.