Trust is central to social cohesion, while hope, though less studied, is a critical sentiment closely tied to well-being and behaviors. Economists have traditionally focused on the long-term determinants of these sentiments; however, trust and hope may be malleable to some extent, especially during critical moments such as electoral periods. We examine short-run fluctuations in social trust and hope, as driven by everyday threats such as media depictions of terrorist attacks, natural disasters, and war. We focus on a politically sensitive period: the week leading up to the June 2024 French parliamentary elections for which an absolute majority win was announced for the extreme-right party. During that week, we conducted online experiments where randomized groups were exposed to short videos triggering specific threats (alternatively terrorism, war, or climate disasters), while a control group viewed a neutral placebo video. The findings reveal significant reductions in social trust and hope with any type of threat, with effects ranging from 12% to 26% of a standard deviation across treatments. For trust, these impacts are notable, especially compared to broader studies relying on quasi-experiments that explore both short- and long-term trends in trust. For hope, we believe this study stands out as one of the first experiment of this type. Heterogeneity analyses show that the effects are primarily driven by center and right-wing voters. For trust, the impact is more pronounced among frequent social media users, suggesting potential selection effects and/or the cumulative influence of repetitive exposure to threats, consistent with "doomscrolling" behavior. Furthermore, the malleable part of trust seems to be associated with emotional dimensions. Indeed, treatments seem to increase the negative correlation between social trust and fear and anger in particular. Hope is more strongly associated with emotions in general (i.e. independently from treatment), but threats initiate a (slight) disconnection between hope and joy. Our results demonstrate that routine threats can destabilize trust and hope, possibly leading to shifts in political attitudes at times of critical choices. Further investigations should also explore resilience mechanisms, to inform effective mitigating policies, and leverage panel data to better understand the dynamics of trust, hope, and emotions over time.