Cross-posted from r/daystrominstitute
In the DS9 episode "Past Tense, Part I", Sisko and Bashir are seemingly accidentally sent to Earth in 2024. But I would posit that this was no accident at all and was actually a plot orchestrated by the Romulans to weaken Earth.
The transporter "accident" was the result of two things: Chroniton particles emitted by the cloaking device, and a microscopic singularity that passed through the system. I suspect that Romulans knew that their cloaks would be susceptible to a singularity, possibly from their usage of artificial ones to power their ships. When they loaned the cloak to the Federation, they knew this aspect, but neglected to mention it, probably because it would've exploited a large weakness in their fleet. But it also could've strictly been part of a covert operation to trigger it at just the right time, as part of an attack in the temporal wars.
Think about it, doesn't it seem very convenient that Sisko and Bashir end up in this very formative period and place in Earth history? It has to have been calculated by the Romulans, or more specifically the AI that Romulans employ to seek out targets in the temporal war, as we are told in SNW's "Tomorrow and Tomorrow and Tomorrow." In that episode, a Romulan agent, Sera, is seen operating in this period on Earth in order to weaken it. This particular instance can't be the singular Romulan plot involving attacks in time.
And lastly, it would seem that the plot worked initially. The Federation disappeared, except for the Defiant, and a Romulan presence was detected on Alpha Centauri. The AI must not have anticipated Sisko's ability to take the place of Bell.
undefined> Would doing that not have opened up just as much risk to the Romulans as to the Federation?
It's possible, but I think that the Romulans would have the upper hand in knowing how to both trigger it and prevent it. It took a while for the Defiant to trigger it, and perhaps the Romulans had some foreknowledge of that. Romulans had been using cloaks of one sort or another for hundreds of years by that point, they have to have experienced this phenomenon long ago. It could even be the method which they employ for their temporal agents. Also, they have to know that the Federation has engaged in time travel both accidentally and willfully, so it's not like they're giving them a key to something they haven't already done.