The problem is, existential threats are more common than not in politics. Nearly every decision can kill, or change who gets killed, on a scope that varies from individual, to global, to more abstract, e.g. values that are just as important as life (freedom, language, culture, family, nature, take your pick - many have given their lives for each of these).
Deport an illegal immigrant? They may get killed back in their more dangerous home country (or die slowly due to less access to medicine), or grow their home economy instead of yours. Let them stay? Maybe they're a dangerous criminal and will kill someone here. Don't deport any? Your culture and nation get diluted into nothing - some value those things highly, others don't, but to the former, that's an existential threat.
Tax fossil fuels? The economy slows, there's less money for hospitals, more crime due to poverty, this can easily kill people, or maybe it's harder to keep up with China. Don't tax them, and now you're taking your chances with global warming.
Spy on everyone's communication? You've just made it much easier for a tyrannical government to arise, and those have killed millions, and trampled values many hold as dear as life itself. Don't spy? Well maybe you miss a few terrorist attacks, but you also have a harder time identifying hostile foreign propaganda, which could have devastating but hard to isolate effects.
Simply put, death, existential threats, threats to democracy, etc., are common in politics, and one cannot talk honestly about it while avoiding their mention. I would say that, unless you cannot keep a cool head in those circumstances, you shouldn't get into politics in any capacity. But of course, those that need this advice won't heed it.