Not only the last election, but the one before that too.
In YC117, former presidential candidate Eliaron Idama was targeted during a rally in Orvolle, which cost the lives of three of his security detail.
I understand that security concerns are valid, but they are not new, and elections at all levels have proceeded largely on schedule in the past.
The Drifters are not unique in being a risk across the Federation, and allowing Aguard to use what is currently a potential threat to delay elections indefinitely establishes a dangerous precedent. Aguard could point to a number of significant threats, and use them as an excuse not to hold elections.
What about the Deathless? Or the Triglavians? Or the monsters under her bed?
If the Federation’s security services are no longer able to meet the challenges, and keep the very basic mechanics of democracy working, then they are not fit for purpose.