This has been brought up elsewhere in the thread, but it's not about the individuals dying. It's about the potential for escalating violence and power grabs that come in its wake.
A MAGA mob that managed to kill Senators would likely cause protests and riots to erupt across the country. Likely worse than we saw last summer. Then you have a major danger of counter protesting, and escalating violence between the groups. Then there's the danger of the possible ways in which the government reacts. We already saw Trump last summer threatening to deploy military on domestic soil. The dominos can continue to fall from there, as violence continues, and power consolidates.
Would that have definitely happened, and would that have definitely threatened to end the republic? I don't know. But it's a threat, nonetheless.
But that’s all fantasy. The country has the national guard for protests in cities which frequently gets deployed and would be used in these scenarios as well. There is no special power grab that can happen legally so he would need a bunch of life long military generals to agree to a coup, in which case the congress protester attack is irrelevant anyway.
A MAGA mob that managed to kill Senators would likely cause protests and riots to erupt across the country. Likely worse than we saw last summer. Then you have a major danger of counter protesting, and escalating violence between the groups. Then there's the danger of the possible ways in which the government reacts. We already saw Trump last summer threatening to deploy military on domestic soil. The dominos can continue to fall from there, as violence continues, and power consolidates.
Would that have definitely happened, and would that have definitely threatened to end the republic? I don't know. But it's a threat, nonetheless.
This comment explains it better than me: https://news.ycombinator.com/item?id=25711602