Interesting how the Senate can now openly debate install a new Emperor.
Legal or not, in practical terms the Senators collectively probably have more power than the Emperor herself so if a substantial majority were in favour of a replacement she might be convinced to abdicate peacefully for the good of the Empire. The issue would be if they were split on the matter but replacement had a narrow majority - that would likely lead to a civil war.
They'd also need to have a replacement to unite behind, and there certainly isn't anyone particularly obvious who actually wants the job.
Vespasian's previous appearances don't give a massive hint on his angle on this:
- there's a bit of routine public sympathy for the family of his murdered colleague
- there's criticism of Aegis as insufficient versus the Thargoids.
Still, there's possibilities there - the Empire, so far, has not been significantly targeted by the Thargoids ... Aegis is not achieving significant results in the fight [1] and with the arrival of a third band of Thargoid raiders independent pilots are also being overwhelmed ... there's a good argument that it's a waste of the Empire's resources to mainly protect its rivals.
I wonder if he intends to use the threat of installing a new Emperor to "compromise" on what he actually wants - a withdrawal from Aegis.
[1] Its only recent public actions have been defence against UA-bombing (which wasn't generally a problem for the Empire in the first place) and an agreement to help protect Ram Tah from interference (who has been independently researching far more effective weapons)