Nikolas Volker is partners with the "Shadow Government" conspiracy
Both have reasons to conspire against Eckhart, and an alliance of convenience allows both to achieve their objectives.- Possibly confirmed. He was seen talking to the Speaker with plans in mind.
- Definitely confirmed later in the season.
Had the series continued, Eckhart would have become President Evil.
The final few episodes don't exactly paint him in a positive light — first, the reveal that when he was VP, he ordered Ray Marks' assassination for defying orders, then his half-joking suggestion to Macabee that they form an entire Elite Army of Agent Xs to serve the executive branch directly (which clearly worries her), and in the final episode his decision to ensure that the Russian Prime Minister doesn't survive being shot. Altogether, this implies that his pragmatic approach to governing was starting him down the slippery slope.- Maccabee would then have had to use her authority under Section Five if she couldn't invoke the Twenty-fifth Amendment. Eckhart's paranoia seems to have started with his attempted assassination, so in a way, Volker created exactly the kind of person he was caricaturing in his "trials".
- Addendum to this WMG: Maccabee would then have been caught between Eckhart's mounting paranoia on the one hand, and the surviving remnants of the "Shadow Government" on the other hand. The S2 finale could then be assumed to end with Maccabee either forcing Eckhart to resign and cite the Twenty-fifth Amendment to elevate her to President, or becoming President after the "Shadow Government" successfully assassinates him, only to in turn be defeated by her and Agent X.