Morden and his associates

Summary
The main part of this story-arc is about the political seduction of Londo Mollari, disgraced scion of a once-powerful family (House Mollari) of the once-powerful Centauri Republic.

Londo is approached by a suave operative who gives his name only as Mr. Morden. Morden has approached all of the major ambassadors on Babylon 5 with the question "What do you want?" He has been rebuffed by most of them (the only answer he receives is from Londo's arch-enemy G'Kar, but Morden apparently decides that this isn't the answer he is looking for), but finally receives an answer from Londo: to restore the glory and power of the great Centauri Republic.

Londo does not really take Morden's offer seriously, however, until Morden is somehow able to deliver to him a priceless Centauri artifact which had been stolen by raiders and feared unrecoverable. Morden gives no explanation of how he was able to obtain the artifact other than to mention that his "associates" are very powerful and can help Londo again, whenever he needs it.

Londo continues to be dismissive of Morden's offer until a very tempting situation arises, and Londo asks Morden if his associates can take a particular aggressive action against Centauri arch-enemies the Narn (G'Kar's people) because Centauri ships are unavailable to do so. Morden's "associates" do in fact accomplish Londo's request while remaining unobserved by either side. Londo is able to claim credit for the feat, which essentially removes his prior disgrace and begins his rise to power.

However, Londo is now increasingly trapped by his association with Morden; he needs Morden's "associates" to continue their displays of power in order to maintain his own power, and Morden becomes increasingly manipulative of Londo as Londo becomes more and more dependent on Morden's "associates" and increasingly addicted to the power they gain for him.

When Morden's "associates" help the Centauri to openly conquer the Narn homeworld, essentially ending the conflict from the Centauri point of view, Londo severs his ties with Morden – who then, having made contacts within Londo's power-group, finds someone less principled to manipulate, in the person of one Lord Refa. Londo finds out about this and manages to prevent Refa from dealing with Morden, but Morden is able to further manipulate the situation so that Londo is willing to work with him once again (as revenge for the murder of Adira, the love of Londo's life, believing that Refa did it, when in fact she was killed by Morden's associates).

Ultimately, Morden's associates turn out to be "The Shadows", an ancient and powerful race whose main goal is to cause war among the various younger races of the galaxy; their true enemy is the Vorlons, another ancient race which generally takes a more paternalistic and controlling approach.

Parallels
This is something of a wild-paranoia theory at this point, but possibly a Londo/Morden scenario of some sort might be able to reconcile (a) George W. Bush's persistent efforts to destroy democracy with (b) persistent belief that he either isn't smart enough or traitorous enough to be so accurately and consistently working to destroy America's power and credibility. If, say, Bush was being given helpful, paternalistic-style advice from a Morden-like figure (say, family friend of Saudi Arabia), he could have been influenced into making choices towards a consistent end-goal not in the 🇺🇸's best interests while thinking all along (due to his inability to grasp long-term strategy) that he actually was acting in those best interests.

Reference

 * Wikipedia: Morden